v'/EPA
United States
Environmental Protection
Agency
Office at Air Quality
Planning and Standards
Research Triangle Park NC 27711
EPA-450/3-87-0100
January 1989
Chromium Final
Emissions from EIS
Comfort Cooling
Towers -
Background
Information for
Promulgated Standards
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EPA-450/3-87-010b
Chromium Emissions from
Comfort Cooling Towers —
Background Information
for Promulgated Standards
Emissions Standards Division
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Air and Radiation
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
January 1989
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This report has been reviewed by the Emission Standards Division of the Office of Air Quality Planning and
Standards, EPA, and approved for publication. Mention of trade naaes or comiercial products is not intended
to constitute endorsenent or recomendation for use. Copies of this report are available through the Library
Services Office (HD-35), U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711,
or froi national Technical Information Services, 5285 Port Royal Road, Springfield, Virginia 22161.
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ENVIRONMENTAL PROTECTION AGENCY
Background Information
and Final
Environmental Impact Statement
for Chromium Emissions From Comfort Cooling Towers
Prepared by:
Drector, Emission Standards Division
U. S. Environmental Protection Agency
Research Triangle Park, M.C. 27711
1. The final rule will eliminate hexavalent chromium emissions
from existing and new comfort cooling towers by prohibiting
the use of hexavalent chromium in these towers. Under
Section 6 of the Toxic Substances Control Act, EPA is
authorized to impose regulatory controls if the Agency finds
that there is a reasonable basis to conclude that the
manufacture, processing, distribution in commerce, use, or
disposal of a chemical substance presents or will present an
unreasonable risk of injury to human health or the
environment.
2. Copies of this document have been sent to the following
Federal Departments: Labor, Health and Human Services,
Defense, Transportation, Agriculture, Commerce, Interior,
and Energy; the National Science Foundation; the Council on
Environmental Quality; members of the State and Territorial
Air Pollution Program Administrators; the Association of
Local Air Pollution Control Officials; EPA Regional
Administrators; and other interested parties.
3. For additional information contact:
Mr. Doug Bell
Standards Development Branch
U. S. Environmental Protection Agency
Research Triangle Park, N.C. 27711
Telephone: (919) 541-5568
4. Copies of this document may be obtained from:
U. S. EPA Library (MD-35)
Research Triangle Park, N.C. 27711
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
iii
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TABLE OF CONTENTS
Page
LIST OF TABLES vi
CHAPTER 1. SUMMARY 1-1
1.1 SUMMARY OF CHANGES SINCE PROPOSAL 1-1
1.2 SUMMARY OF IMPACTS OF PROMULGATED ACTION 1-3
1.2.1 Alternatives to Promulgated Action 1-3
1.2.2 Environmental and Health Impacts of
Promulgated Action.. 1-3
1.2.3 Energy and Economic Impacts of
Promulgated Action 1-3
1.2.4 Other Considerations 1-4
1.2.4.1 Irreversible and Irretrievable
Commitment of Resources 1-4
1.2.4.2 Environmental and Energy Impacts
of Delayed Action 1-4
1.2.4.3 Urban and Community Impacts 1-4
CHAPTER 2. SUMMARY OF PUBLIC COMMENTS 2-1
2.1 WATER TREATMENT PROGRAM PERFORMANCE 2-6
2.2 HEALTH EFFECTS/RISK 2-22
2.3 REGULATORY APPROACH 2-35
2.4 RECORDKEEPING AND REPORTING REQUIREMENTS 2-45
2.5 ECONOMIC AND COST IMPACT 2-53
2.6 SELECTION OF SOURCE CATEGORY 2-66
2.7 MONITORING AND CONTROL 2-69
2.8 LEGAL CONSIDERATIONS 2-71
2.9 MISCELLANEOUS 2-72
2.10 REFERENCES FOR CHAPTER 2 2-73
APPENDIX A. CALCULATION OF NATIONWIDE COST EFFECTIVENESS A-l
APPENDIX B. APPROACH TO DATA GATHERING EFFORT B-l
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LIST OF TABLES
COOLING TOWERS
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1.0 SUMMARY
On March 29, 1988, the Environmental Protection Agency (EPA) proposed
a rule to prohibit the use of hexavalent chromium (Cr*6)-based water
treatment chemicals in comfort cooling towers (CCT's) and the distribution
in commerce of these chemicals for use in CCT's. The proposed rule was
issued under the authority of Section 6 of the Toxic Substances Control
Act (TSCA). The rule affects users of CCT's including hospitals, hotels,
educational facilities, office buildings, and retail shopping malls.
Persons who distribute in commerce water treatment chemicals containing
Cr+fi would be affected also.
Public comments were requested on the proposal in the Federal
Register. There were 27 letters submitted concerning the rule. Sixteen
letters were from water treatment chemical companies, two from CCT users,
four from industry trade groups, three from water treatment consultants,
one from a publicly owned treatment works, and one from an environmental
group. In addition, five speakers presented comments at the public
hearing. Two of the speakers were from one water treatment company, two
were water treatment consultants, and one was from a company that
manufactures sodium dichromate and other chromium chemicals.
The comments submitted, along with responses to these comments, are
summarized in this document. The summary of comments and responses serves
as the basis for the revisions made to the rule between proposal and
promulgation.
1.1 SUMMARY OF CHANGES SINCE PROPOSAL
In response to public comments and as a result of EPA revaluation,
the nationwide cost impact and risks have been reanalyzed, and several
changes have been made in the proposed rule. The changes in the rule
involve (1) revising the labeling, recordkeeping and reporting
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requirements; (2) clarifying the prohibitions on use and distribution of
Cr"1" ; and (3) adding and revising definitions.
A statement was added to the final rule to clarify that the use of
Cr* -based water treatment chemicals in industrial cooling towers (ICT's)
and closed cooling water systems, and the distribution in commerce of the
chemicals for use in these facilities, are not prohibited. Minor changes
were made to the warning label requirement to indicate that CCT's are
towers that are open water recirculation devices and to clarify that
inhalation of Cr+s air emissions increases the risk of lung cancer.
Two changes were made to the recordkeeping and reporting requirements
of the final rule. First, the requirement that records be maintained by
water treatment chemical distributors of shipments of nonchromate
chemicals to CCT's has been deleted. Second, the reporting requirement by
distributors that provide only nonchromate water treatment chemicals also
has been deleted. The EPA has reevaluated the need for these records and
reports and has determined that enforcement of the rule would be
adequately accomplished by other provisions.
Definitions have been included in the rule for the new terms "cooling
system," "closed cooling water system," and "chilled water loop"; and the
definition of "water treatment chemicals" has been revised. The new and
revised definitions clarify that the labeling, recordkeeping, and
reporting requirements apply to cooling systems rather than to cooling
towers. The definition of "water treatment chemicals" has been revised by
deleting the word "biocides." This change has been made because biocides
are regulated under the Federal Insecticide, Fungicide, and Rodenticide
Act (FIFRA). Definitions also were added for the terms "distributor" and
"Cr*6 chemicals" to clarify the intent of the rule.
The statement of applicability of this rule was revised slightly.
This change is of an editorial nature to clarify the original intent of
the rule, to account for changes in the recordkeeping and reporting
requirements, and to improve compliance monitoring efficiency.
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1.2 SUMMARY OF IMPACTS OF PROMULGATED ACTION
1.2.1 Alternatives to Promulgated Action
Regulatory control alternatives considered during development of the
rule are discussed 1n Chapter 6 of the background Information document
(BID) (EPA-450/3-87-010a) for the proposed rule. These alternatives
reflect different levels of emission control, and they remain unchanged
from proposal.
1.2.2 Environmental and Health Impacts of Promulgated Action
Under the final rule, baseline Cr+s emissions from about 37,500 CCT's
will be reduced from about 33 megagrams per year (Mg/yr) (34 tons per year
[tons/yr]) to zero. This emission reduction is based on a best-estimate
emission factor rather than the range used in Chapter 4 of the proposal
BID. A range of emission factors was used at proposal because of the
uncertainty associated with the factors for Cr"*"6 emissions from CCT's.
Since proposal, additional test data have been obtained which, in
combination with the original data, were used to develop the best estimate
emission factor.
The best estimate of the emissions for CCT's was used to reanalyze
the risk to public health from Cr"*"6. The revised risk estimates indicate
that the nationwide annual incidence of lung cancer attributable to Cr"*"6
emissions from 37,500 CCT's is estimated to be about 20 cases per year.
The revised maximum individual risk is estimated to be 2 x 10"1*. The
final rule will reduce these risks to zero.
Water and solid waste impacts are unchanged from those presented in
Chapter 9 of the proposal BID. Therefore, with the changes in the
emissions and risk estimates noted in this section, the analysis of the
environmental impact in the proposal BID becomes the final Environmental
Impact Statement for the promulgated rule.
1.2.3 Energy and Economic Impacts of Promulgated Action
The rule would have only negligible impacts on energy consumption
from increased power requirements for automated control systems. This
remains unchanged from proposal.
The cost impacts of the proposed rule are presented in Chapter 7 of
the proposal BID. Since proposal, the automatic control equipment and
chemical treatment program costs have been revised. The average automatic
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control equipment cost has increased from $500 to $1,400. The cost
difference between chromate and nonchromate programs has increased from
$60/raillion pounds (M Ib) of blowdown to $85/M Ib of blowdown. Based on
these changes, the annual cost of compliance per CCT ranges from $300 to
$1,600 and the total annual nationwide cost is projected to be about $20
million. At proposal, the total annual nationwide cost was estimated to
be $9.4 million.
The economic impacts of the proposed rule are presented in Chapter 8
of the proposal BID. These impacts have been revised based on the new
costs discussed above. However, the increased cost is not expected to
have a significant economic impact on owners or tenants of affected
properties. The average impact on rental rates for the smallest towers is
estimated to be less than $0.45 per square meter (m2) ($0.04 per square
foot [ft2]), or less than 1 percent if all costs were passed on in the
form of increased rental rates. This is an increase from $0.12/m2
($0.01/ft ) at proposal. The impact on rental rates decreases as tower
size increases.
1.2.4 Other Considerations
1.2.4.1 Irreversible and Irretrievable Commitment of Resources.
Other than the negligible amount of fuels required for power generation
for the control systems, there is no apparent irreversible or
irretrievable commitment of resources associated with this rule.
1.2.4.2 Environmental and Energy Impacts of Delayed Action. Delay
in implementing the rule would result in a delay in emission reduction of
Cr*6 from CCT's and delay in realization of other estimated impacts.
1.2.4.3 Urban and Community Impacts. The rule will have a positive
impact on urban areas and communities because of decreased Cr"1"6
emissions. There should be no decrease in employment in urban areas and
communities because the revised economic analysis indicates that the rule
would not have a significant economic impact on owners or tenants of
affected properties.
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2. SUMMARY OF PUBLIC COMMENTS
A total of 27 letters commenting on the proposed rule and the
proposal BID for the prohibition of Cr+6 chemicals in CCT's were
received. In addition, five speakers commented on the proposed rule at
the public hearing. Comments from the public hearing on the proposed rule
were recorded, and a transcript was placed in the project docket. One
letter was also received clarifying information presented at the public
hearing. A list of those who submitted comments in writing and of those
who presented comments at the public hearing is given in Table 2-1. The
docket number assigned to their correspondence and to the public hearing
transcript (docket number OPTS-61012, category IV) also is given for each
commenter listed on the table.
For the purpose of orderly presentation, the comments have been
categorized under the following topics:
1. Water Treatment Program Performance;
2. Health Effects/Risk;
3. Regulatory Approach;
4. Recordkeeping and Reporting Requirements;
5. Economic and Cost Impact;
6. Selection of the Source Category;
7. Monitoring and Control;
8. Legal Considerations; and
9. Miscellaneous.
The comments, the issues they address, and EPA's responses are discussed
in the following sections of this chapter.
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TABLE 2-1. LIST OF COMMENTERS ON PROPOSED RULE TO PROHIBIT THE USE OF
HEXAVALENT CHROMIUM CHEMICALS IN COMFORT COOLING TOWERS
Docket
Item No.a Commenter and affiliation
IV-D-9 Mr. Victor A. Denslow
Chemical Regulations Services
4151 Woodland Avenue
Western Springs, Illinois 60558
IV-0-10 Mr. Ed Carlyle, Jr.
Pretreatment Inspector
City of Bossier City
Post Office Box 5337
Bossier City, Louisiana 71171-5337
IV-0-11 Ms. Elaine Zack
Regulatory Specialist
Mogul Division of the Dexter Corporation
Post Office Box 200
Chagrin Falls, Ohio 44022
IV-0-12 Mr. John T. Brophy
Quad-City Chemicals Company
2328 Eastern Avenue
Davenport, Iowa 52803
IV-D-13 Mr. William J. Ward, P.E.
William J. Ward & Associates
Post Office Box 14681
Lenexa, Kansas 66215
IV-D-14 Mr. Vincent J. Saputo
Globe Environmental Corp.
21 Business Park Drive
Branford, Connecticut 06405
IV-0-15 Mr. Wesley C. Geen
Geen Industries, Inc.
Post Office Box 333
Itasca, Illinois 60143
IV-0-16 Mr. Richard J. Nagle
President
Betz Entec, Inc.
508 Prudential Road
Horsham, Pennsylvania 19044
(continued)
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TABLE 2-1. (continued)
Docket
item No. Commenter and affiliation
IV-0-17 Mr. Jeff Girard
President
Girard Chemical Company
992 Stuart Road
Bartlett, Illinois 60103
IV-0-18 Mr. Shaun L. Helmhout
Senior Registration Specialist
Buckman Laboratories International, Inc.
Post Office Box 8305
1256 North McLean Boulevard
Memphis, Tennessee 38108-0305
IV-0-19 Ms. Cindy Matthews
Vice President
Guardian-IPCO, Inc.
Post Office Box 43067 .
6606 Cahaba Valley Road
Birmingham, Alabama 35243
IV-D-20 Mr. Walter A. Weas, Sr.
President
Weas Engineering, Inc.
Post Office Box 816
Carmel, Indiana 46032
IV-0-21 Mr. Daniel H. Brown
General Manager
Chem-Serv
2955 West Clarendon
Phoenix, Arizona 85017
IV-0-22 Mr. Ronald C. Bond
President
Bonco Manufacturing Corp.
Post Office Box 521
Jefferson, Georgia 30549
IV-0-23 Mr. Larry T. Chewning
General Manager
Southeastern Laboratories, Inc.
Post Office Box 1715
Goldsboro, North Carolina 27533-1715
(continued)
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TABLE 2-1. (continued)
Docket
Item No. Commenter and affiliation
IV-0-24 Mr. Thomas M. Laronge
Chairman, Government and Intersodety Committee
National Association of Corrosion Engineers
Post Office Box 218340
Houston, Texas 77218
IV-D-25 Mr. Kenneth L. Zacharias
Associate Director, Industry Affairs
National Paint and Coatings Association
1500 Rhode Island Avenue, N.W.
Washington, D.C. 20005
IV-0-26 Ms. Karen Florini
Attorney
Environmental Defense Fund
1616 P Street N.W.
Washington, D.C. 20036
IV-0-27 Mr. Richard A. Hoffmann, P.E.
Hoffman & Felge, Inc.
223 Katonah Avenue
Katonah, Mew York 10536
IV-D-28 Dr. Ross E. Jones
Corporate Toxicologist
Occidential Chemical Corporation
Post Office Box 728
360 Rainbow Boulevard South
Niagara Falls, New York 14302
IV-D-29 Mr. John P. Herrmann
Chief, Environmental Services Office
Lyndon B. Johnson Space Center
Houston, Texas 77058
IV-0-30 Mr. Brent W. Chettle, P.E.
18845 Kilfinan Street
Northridge, California 91326
(continued)
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TABLE 2-1. (continued)
Docket
Item No. Commenter and affiliation
IV-0-31 Mr. R. L. Hagerman
Research Associate, Regulatory Compliance
The Dow Chemical Company
1803 Building
Midland, Michigan 48674
IV-D-32 Mr. Greg D. Sefton
Communications Manager
Mitco Water Laboratories, Inc.
Post Office Box 1435
Winter Haven, Florida 33882-1435
IV-0-33 Mr. Norman A. Alston
President
Cooling Tower Institute, Inc.
Post Office Box 73383
Houston, Texas, 77273
IV-D-34 Mr. Louis J. Koenig, Jr.
Technical Director
O'Brien Industries, Inc.
2686 Lisbon Road
Cleveland, Ohio 44104
IV-D-35 Mr. Thomas M. Laronge
Chairman, Government and Intersociety Committee
National Association of Corrosion Engineers
Post Office Box 218340
Houston, Texas 77218
IV-F-1 Transcript of Public Hearing on Proposed Rule for the
Prohibition of Hexavalent Chromium Chemicals in Comfort
Cooling Towers. Speakers were:
Dr. Charles Smith, Mitco Water Laboratories, Inc.
Mr. Greg D. Sefton, Mitco Water Laboratories, Inc.
Dr. Ross E. Jones, Occidental Chemical Corporation
Mr. Carl T. Murphy, Apollo Beach, Florida
Mr. Mark Crissman, West Palm Beach, Florida
dThe docket number for this project is OPTS-61012. Dockets are on file at
EPA Headquarters in Washington, D.C., and at the Office of Air Quality
Planning and Standards in Durham, North Carolina.
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2.1 WATER TREATMENT PROGRAM PERFORMANCE
2.1.1 Comment
Four commenters (IV-D-13, -14, -15, and -17) believe that many
technically acceptable alternatives to Cr*6-based water treatment
chemicals are available. Three of the commenters (IV-0-14, -15, and -17)
Indicated that successful nonchromate treatment programs contain various
combinations of phosphates, phosphonates, molybdate, zinc, azoles, and
polymers. One commenter (IV-D-14) recommends, for example, that ice
skating rinks using chromate with calcium chloride switch to calcium
chloride and zinc. Another commenter (IV-D-13) says that acceptable
alternatives have been proven; however, these substitutes generally are
somewhat more expensive than chromate and may require more precise
controls than chromates to achieve equal corrosion protection.
Response. No response necessary.
.2.1.2 Comment
Three commenters (IV-0-24, -27, and -29) indicated that chromate
programs offer the best corrosion protection available. One commenter
(IV-D-24) indicated that there is no known single substitute for Cr+s that
can provide similar corrosion inhibiting properties, or that is as easy to
control, as forgiving to upsets, and as cost effective. The commenter
believes that stating in the proposal BID and the preamble that
nonchromate substitutes exist appears certain to prejudice and/or mislead
purchasers in selection, purchasing, and utilization practices of the
"misnomered" nonchromate substitutes.
Response. Many nonchromate water treatment programs exist that can
be used as alternatives, or substitutes, for chromate programs. These
alternative programs are completely separate and self-contained; a
nonchromate chemical cannot simply be substituted for chromate in an
existing chromate program. Although most nonchromate programs can be used
in any CCT, the water quality parameters and types of airborne
contaminants in each system should be evaluated prior to a switch in
treatment programs to determine the site-specific application strategy.
The evaluation will indicate the level of inhibitor or product that should
be maintained in the recirculating water, the amount of acid that should
be added (if any), the number of cycles of concentration that can be
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tolerated, the types and amounts of biocides that should be used, and the
type of additional control equipment that should be Installed.
Typically. nonchro«ate programs are more difficult to control and
cost more than chro»ate programs. However, when properly controlled and
maintained, their effectiveness has been clearly demonstrated "^r a w *
range of conditions. In the proposal BID, the results achieved n CCT s
used at a research center In Virginia were presented. In the 3 to
4 months after switching to a phosphate-based treatment program accept-
able corrosion rates as measured on carbon steel coupons were about Z mils
per year (m1ls/yr). In subsequent months, even lower rates were achieved
as the CCT operators became more familiar with the program and the
monitoring and control procedures. In this case, the operators believe
that the nonchromate program performance 1s similar to that of the previ-
ously used 5- to 10-parts per million (pp.) cnromate program. At other
sites CCT operators also Indicated that acceptable corrosion rates were
being achieved with nonchromate programs. The makeup water used In most
of these CCT's was good quality water.' Even 1n poor quality makeup wat
(soft water or water that contains high chloride, hardness, and alkalin ty
levels), acceptable corrosion rates (<2 mils/yr) have been achieved with
nonchromate programs (see responses to Comments 2.1.6 and 2.1.7).
2.1.3 Comment
Two commenters (IV-0-27 and IV-0-29) questioned whether EPA had
adequately considered the Impact on existing, older CCT systems of
switching from Cr+6-based water treatments to nonchromate treatments One
counter (IV-0-29) believes that in an existing system being treated with
a chromate program, the "protective coating" within piping and equipment
would be disrupted during the transition from "proven" chromate treatments
to "nonproven" nonchromate treatments. This disruption would lead to
increased fouling and to pinhole leakage at least until the replacement
inhibitor becomes stabilized. Thus, according to the comments, existing
towers, especially older systems, converted to "nonproven" inhibitors
could experience significant downtime and disruptions.
One commenter (IV-0-27) believes that no nonchromate program can
operate successfully 1n CCT's that are corroded, but are still operative,
or that contain deposits. In addition, the commenter indicated that ,t is
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essentially impossible to clean a corroded system. The commenter believes
the issue of corroded systems must be addressed because many building
owners inherit a CCT system that has been neglected. The commenter also
believes that the carbon steel piping rather than the condenser tubes is
the most critical component in many CCT systems because underdeposit
corrosion is found in piping between the condenser and the CCT. In the
CCT's the commenter has observed, the condenser tubes have been properly
maintained in all cases. The commenter has examined samples of corroded
carbon steel pipe from CCT systems in New York City that used chromate
treatment programs and has found an average corrosion rate of about 7 to
10 mils/yr. For systems using molybdate treatment programs, the commenter
has observed corrosion rates of 7 to 30 mils/yr. To illustrate the
severity of the corrosion rate with molybdate treatment programs, the
commenter indicated that pipes in some systems had operated satisfactorily
on chromates but had failed because of underdeposit corrosion within only
1 to 2 years after switching to molybdate treatment. The commenter
believes that these rates are the norm and that the corrosion rates
presented in Table 3-1 of the proposal BID are for ideal, clean samples,
which rarely exist in actual CCT systems.
Response. The EPA has investigated the impact of switching CCT's to
nonchromate treatments. According to water treatment chemical
distributors, the majority of CCT's, including older systems, using
chromate programs are not corroded and can be easily switched to
nonchroraate programs. Switching a clean, chromate-based CCT system to a
nonchromate program can be accomplished by switching the inhibitor feed
and allowing the chemicals in the new program to repair defects in the
chromate film as they develop. However, if a system is heavily corroded,
it may be necessary to clean the system before a nonchromate program can
be implemented successfully. In many cases, on-line cleaning is
successful. On-line cleaning often is performed with chelating agents
such as sodium or ammonium salts of ethylenediamine tetraacetic acid
(EDTA).2'3 Various combinations of phosphates, phosphonates, polymeric
dispersants, and synthetic detergents also have been used for on-line
cleaning. For example, a program containing molybdate and a polymeric
diol has been developed that cleans existing corrosion and prevents its
recurrence.
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For some heavily corroded systems, on-line cleaning may not be
adequate. In these cases of severe corrosion, it may be necessary to shut
down the system to perform a stronger cleaning effort. Chelating agents
and other chemicals at elevated temperatures or dilute acid solutions are
often used in these cases. According to a cleaning contractor, the
procedure typically takes 1 to 3 days. After the recirculation water is
discharged or blown down to remove the cleaning chemicals, the system
should be repassivated with high levels of the inhibitor product. The
high levels should be maintained for up to 2 days depending on the type of
treatment, the temperature, and the level of product maintained in the
CCT. After the system is repassivated, it should be heavily blown down
again until the maintenance inhibitor level is reached. At this time, the
pH also should be adjusted to the maintenance level.2'3
The CCT system is susceptible to fouling during cleaning and to high
corrosion rates during both the cleaning and repassivation procedures, but
the problems are minimized by proper execution of the procedures. Fouling
is controlled by monitoring the suspended solids levels, adjusting the
concentration of cleaning chemicals, and adjusting the blowdown. The
amount of corrosion is minimized by including various inhibitors and other
additives in the cleaning solution. During the repassivation phase, the
system is protected by the high concentration of inhibitor product.
Evidence that switching clean systems to nonchromates does not cause
downtime and disruptions was provided for CCT's used at a research center
in Virgina. As described in the proposal BID, EPA evaluated available
corrosion results during the 3 to 4 month period after the CCT's were
switched from chromate to phosphate treatment programs. These data
indicated that no leaks developed in the CCT systems and that acceptable
carbon steel corrosion rates of about 2 mils/yr were achieved.1
Evidence that many corroded systems can be cleaned without downtime
as nonchromate treatment programs are implemented is provided by the
experiences at a refinery in Kansas and by a tire manufacturer in the
southeastern U.S. The refinery tower (an ICT) was extremely corroded when
the decision was made to switch to a phosphate treatment program.
Excessive corrosion rates were not observed while cleaning chemicals were
circulated along with the new nonchromate inhibitor formulation.
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Corrosion rates on carbon steel coupons averaged 1 mil/yr in the 5 months
following the switch. There has been no pitting or underdeposit corrosion
in the piping in the 10 years since the switch.5 The tire manufacturer in
the southeastern U.S. had been using an all-organic program with soft,
naturally corrosive makeup water in an Industrial tower. High average
corrosion rates of 5.75 mils/yr and pitting of 12 mlls/yr were observed on
carbon steel coupons, and heavy deposition of both corrosion products and
iron phosphate was occurring. Upon switching to a molybdate program with
a diol dispersant, the blowdown began to show evidence of deposit
removal. Corrosion coupons examined over the first 6 months after
switching indicated that the average corrosion rate had been reduced to
0.32 m1l/yr with no pitting. In addition, pipe plugging was eliminated,
there was no evidence of iron oxide or iron phosphate deposits anywhere in
the system, and there was no indication of underdeposit corrosion or high
corrosion in the piping.1*
Evidence that even heavily corroded systems can be cleaned with only
a minimum of downtime was provided by a CCT user in New York City. The
CCT user contracted with a cleaning company to clean a heavily corroded
CCT system with 20 chillers-on 6 floors. A scheduled shutdown of 3 days
was necessary for the cleaning procedure. No leaks developed in the
system during this time.5
In summary, the results of these cleaning efforts show that it is
possible to clean corroded systems and subsequently control corrosion and
deposition with nonchromate programs, even in CCT's using poor quality
water. Additional information about the performance of various treatment
programs under poor quality water conditions is provided in the responses
to Comments 2.1.6 and 2.1.7.
The commenter has misunderstood the purpose of Table 3-1 of the
proposal BID. The corrosion rates in the table do not refer to average
corrosion rates achievable under specific conditions as suggested by the
commenter. The purpose of the table is to indicate how various rates are
perceived by the corrosion and water treatment industry as a whole. For
example, a carbon steel corrosion rate of 7 mils/yr would be considered
moderate by most industry representatives, even though in specific
applications it might be the best rate that can be achieved. Therefore,
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EPA believes the rates presented in the table are appropriate for the
intended purpose.
2.1.4 Comment
One commenter (IV-D-27) stated that no CCT system can remain free of
airborne dirt because 1t 1s introduced into the system, coating the Inner
pipe surfaces, during the construction of the building and 1s always being
generated by other construction surrounding the building. The commenter
also indicated that unless the inner pipe surfaces are kept clean from
dirt deposits, underdeposit corrosion is inevitable.
Response. The commenter is correct that airborne dirt near a CCT
will be drawn into the system and, if uncontrolled, may deposit and lead
to underdeposit corrosion. Typically, water treatment distributors
successfully combat this problem by including dispersants in their water
treatment programs. However, one water treatment distributor agreed with
the commenter that under typical operating procedures, suspended solids
cause deposition and underdeposit corrosion in some CCT systems in New
York City. According to the distributor, part of the problem is that the
airborne dirt levels in New York City are especially high, and the water
is soft. In soft water applications, the CCT's operate at high cycles of
concentration, which is defined as the ratio of the concentration of
either the dissolved solids or the conductivity of the recirculation water
to that in the makeup water. High cycles of concentration (i.e., 10 to
15) are necessary in New York City to achieve concentrations of calcium
compounds in the recirculation water that are high enough to result in
water that tends to be scale-forming rather than corrosive. Scale-forming
water is important for successful operation of most nonchromate treatment
programs. In New York City, operating with high cycles of concentration
also produces especially high concentrations of suspended solids in the
CCT system. The distributor indicated that CCT's in other cities such as
Hartford, Connecticut, and Boston, Massachusetts, also use soft water and
operate with high cycles of concentration, but these CCT's do not have
problems with deposition and underdeposit corrosion when operated
properly.7
In responding to the comment, EPA also obtained information
indicating that deposition could, in part, be attributed to slow flow or
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stagnant water conditions, especially in CCT systems used in some new
multistory buildings. The new systems consist of a CCT on the roof and
one or more chillers per floor. When space cooling is not needed by a
particular chiller, it is turned off and water flow "is stopped. This
reduces energy costs, but increases the opportunity for deposition of
suspended solids. Typically, CCT's also are shut off for several hours
each night.
In cases where .control of deposition and underdeposit corrosion is
inadequate with an existing nonchromate treatment program, several options
are available to bring the system under control. First, another treatment
program with different dispersants may be more effective. Second, slow
flow or stagnant areas of the CCT system should be eliminated. This may
require that circulation be maintained (at least periodically) through all
chillers. A third option, typically recommended by water treatment
distributors, is to reduce the operating cycles of concentration. Because
this option results in recirculating water that tends to be less scale-
forming (or more corrosive) a treatment program with higher levels or
additional types of corrosion inhibitors may be necessary. In the event
that the operators do not want to use these options or they are
unsuccessful, a fourth option would be to install a sidestream filter to
remove suspended solids.
2.1.5 Comment
One commenter (IV-D-27) believes that the use of corrosion coupons to
evaluate the effectiveness of a treatment program is misleading because
they only measure the corrosivity of the water, not the actual under-
deposit corrosion rate.
Response. The commenter is correct that coupons can only measure the
effectiveness of a treatment program at creating and/or maintaining a
protective film or barrier in a particular type of water. However, as
indicated in the response to Comment 2.1.4, deposition should not be a
problem in a properly maintained CCT system. If deposition is occurring,
the program is not performing well, and adjustments should be made or the
treatment program should be replaced.
Although pitting or underdeposit corrosion in tubes can be measured
with an Eddy current test when the system is shut down, there is no way to
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measure underdeposit corrosion in piping without removing the pipe from
the system. Consequently, a preventive program based on the potential for
deposition is the best approach to dealing with corrosion. (See the
response to Comment 2.1.4 for a discussion of such programs.)
2.1.6 Comment
One commenter (IV-0-27) stated that EPA did not address the Impact of
differences in water conditions on the performance of corrosion inhibitor
systems and that the proposal BID did not mention scale-forming or
corrosive waters. If a scale-forming water is used in the CCT, corrosion
problems are minimal. However, when soft, corrosive waters (such as those
in the New York City metropolitan area) are present, the commenter
believes that the results of corrosion tests would be different than the
results with scale-forming water. The commenter believes that corrosive
waters similar to those in New York City exist in the northwestern U.S.
Response. To respond to. the comment, EPA obtained additional
information about the performance of nonchromate treatment programs in
CCT's using soft water from eight water treatment chemical distributors.
Case history performance data provided by four of the distributors
indicate that acceptable corrosion rates (0.3 to 2.5 mils/yr) can be
achieved with nonchromate treatment programs in soft water applications.
These corrosion rates are within the range of corrosion rates achieved
with nonchromate programs in scale-forming water and are also comparable
to corrosion rates achieved with chromate programs. Much of the
performance data are for programs used in ICT systems. The information
from ICT's is applicable to CCT's because both types of cooling towers use
carbon steel distribution pipes, and the primary concern of the commenter
is with corrosion of the carbon steel pipes in CCT systems. Four other
water treatment chemical distributors did not provide data but they did
confirm the effectiveness of nonchromate programs. The data and
information obtained from all eight distributors are discussed below and
in docket item IV-B-4 (docket items referenced in this BID are in docket
number OPTS-61012).
Performance data were provided for a CCT in the northeastern U.S.
that uses soft makeup water. The total hardness in the makeup water was
28 ppm, the alkalinity was 20 ppm, and the total dissolved solids (TDS)
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level was 155 ppm. This tower operated with about six cycles of
concentration. The treatment program was a molybdate/organophosphate
blend that the water treatment chemical distributor claims can be used
effectively even in water with zero hardness. Mild steel and copper
corrosion rates as measured with coupons were about 0.9 m1l/yr and
0.2 mil/yr, respectively. The distributor providing this service
considers treatment programs successful if they achieve carbon steel
corrosion rates of less than 3 mils/yr.
At an ICT using makeup water with a total hardness of 15 ppm, carbon
steel corrosion rates of less than 1.5 mils/yr were achieved. The
treatment program, supplied by another water treatment chemical
distributor, consisted of a molybdate/ortnophosphate/azole formulation
that was fed at a rate to yield a molybdate residual of 4 to 6 ppm. A
nonionic dispersant also was added, and deposition was insignificant.
Results of laboratory corrosion studies of various nonchromate
formulations in low ionic strength water were provided by one water
treatment chemical distributor. The total hardness of the tested water "
was 96 ppm, the alkalinity was 72 ppm, the conductivity was
269 micromhos (umhos), and the Langelier Saturation Index (LSI) was 0.
The LSI indicates the corrosion or scale-forming tendencies of water;
positive LSI values .indicate that the water tends to be scale forming, and
negative LSI values indicate that the water tends to be corrosive.
Corrosion rates of 2.0 mils/yr without pitting were achieved in the
laboratory with high phosphate and molybdate/orthophosphate/azole formula-
tions. The distributor considers treatment programs to be successful if
corrosion rates of less than 3.0 mils/yr are achieved.
Another successful application of a nonchromate program was for an
ICT using soft water; the makeup and recirculating water contained total
hardness levels of less than 2 ppm and 14 ppm, respectively. The treat-
ment program, supplied by the third water treatment chemical distributor,
consisted of orthophosphate and polyphosphate for mild steel protection
and tolyltriazole for admiralty brass protection. Mild steel corrosion
rates as measured by untreated coupons ranged from 2.2 mils/yr to
2.7 mils/yr. Corrosion rates on pretreated coupons ranged from 0.7 mil/yr
to 1.6 mils/yr. Pretreated coupons are chemically passivated similar to
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the way the metal surfaces in the cooling system are passivated. This
distributor believes that actual system corrosion rates are represented
more accurately with pretreated coupons than with untreated coupons.
An ICT system at a tire manufacturing plant In the southeastern U.S.
using makeup water that contains low hardness and low alkalinity was able
to achieve very low corrosion rates with a nonchromate program. Actual
hardness and alkalinity values were not available, but an average corro-
sion rate of 0.32 mil/yr with no pitting was achieved with a molybdate and
polymeric diol treatment program supplied by a fourth water treatment
chemical distributor. In addition, there was no deposition or
underdeposit corrosion in the system piping. This corrosion rate is as
good as or better than results obtained with chromate treatment programs.
Four water treatment chemical distributors indicated that nonchromate
treatment programs provide acceptable results when soft makeup water is
used, but they did not present case history information. One distributor
indicated that if the hardness in the recirculating water is less than
about 50 ppm, average corrosion rates of 1 to 2 mils/yr with no pitting
can be achieved only with zinc programs. A second distributor indicated
that average corrosion rates of 2 to 3 mils/yr without pitting are
achieved with molybdate treatment programs in CCT's that use makeup water
with calcium hardness levels as low as 14 to 20 ppm and alkalinity of 6 to
9 ppm These CCT's operate with 10 to 15 cycles of concentration so that
the recirculating water has a positive LSI. A third distributor indicated
that "excellent" results are obtained in CCT's in Greenville, South
Carolina, where the water has total hardness levels of only 2 to 3 ppm.
The fourth distributor believes that average corrosion rates of less than
2 mils/yr can be obtained with treatment programs based on various
combinations of zinc, phosphonate, orthophosphate, and molybdate when soft
makeup water (e.g., total hardness of about 18 ppm and total alkalinity of
about 10 ppm) is used. The distributor recommends that the system be
operated with 10 or more cycles of concentration to obtain a positive LSI
and more than 100 ppm of calcium hardness. In addition, the pH should be
maintained above 7.5, which may require the addition of caustic soda.
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In summary, the case history performance data and other information
obtained from the water treatment chemical distributors show that many
nonchromate treatment programs in soft water applications can achieve
acceptable carbon steel corrosion rates of less than 2 mils/yr. Several
programs can achieve corrosion rates of less than 1.5 mils/yr. These
corrosion rates are comparable with corrosion rates achieved in scale-
forming water, and the lowest corrosion rates are similar to the rates
achieved with chromate programs.
2.1.7 Comment
One commenter (IV-F-1 [Smith]) indicated that no nonchromate program
can successfully control corrosion when the water has high chloride,
hardness, and alkalinity levels (e.g., along the coast of Florida),
especially when operators provide poor daily maintenance. Typically, acid
must be added to reduce the alkalinity and control scale. However, acid
addition increases the corrosivity of the water. In addition, for waters
that also have high levels of chlorides, it is imperative that a tight
inhibitor film is formed and maintained to withstand low pH excursions or
high chloride excursions because the presence of chloride ions increases
the corrosivity of the water.
When contacted for clarification, the commenter recommended that the
sodium chloride concentration in recirculating water be limited to about
600 ppm. According to the commenter, CCT's able to operate at about
5 cycles of concentration without exceeding this level are using good to
moderate quality water. Based on the original comment, the lowest
corrosion rates that the commenter has been able to achieve with
nonchromate programs in such water are 2 to 4 mils/yr with some molybdate/
dispersant programs. Zinc, all-organic, and molybdate programs without
dispersants or only low levels of molybdate achieved corrosion rates of 4
to 15 mils/yr. Because many of the commenter's customers specify that
treatment programs must limit mild steel corrosion to less than 2 mils/yr,
the programs described above would be unacceptable to them. According to
the commenter, many water supplies in Florida contain 200 to 400 ppm NaCl,
and some have higher levels. For CCT's using this water, higher than
recommended chloride levels would need to be maintained in the CCT for it
to operate at 5 cycles of concentration. The commenter indicated that
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higher chloride levels would result in higher corrosion rates than those
presented above. The commenter also indicated that the CCT could operate
successfully at lower cycles of concentration so as not to exceed the
maximum recommended chloride concentration, but this would require more
makeup water and higher cost (see Comment 2.5.2 for additional discussion
of the cost impact).
The commenter also Indicated that new programs tested in the
laboratory have achieved corrosion rates of 1 to 3 mils/yr (with no
pitting) in water containing 500 to 1,000 ppm NaCl. In a more recent
contact, the commenter indicated that corrosion rates of 1 to 4 mils/yr
(with no pitting) have been achieved with the new program in the field.
The commenter believes that the field results were not as good as the
laboratory results because the treatment programs may not have been
controlled as well in the field. Another commenter (IV-F-1 [Crissman])
described the severe scaling and underdeposit corrosion problems that
occurred in two systems using nonchromate treatment programs in poor
quality Florida water.
Response. To respond to these comments, additional information about
the performance of nonchromate water treatment programs for CCT's in areas
where the makeup water has high chloride, hardness, and alkalinity levels
was requested from water treatment companies and other contacts. The
information provided by five water treatment companies indicates that
nonchromate treatment programs that provide adequate control of corrosion
in CCT's using such water are available. Corrosion rates, as measured
with carbon steel coupons, at two CCT's and two ICT's using makeup water
similar to water in Florida ra'nged from less than 1 mil/yr to
1.33 mils/yr. In addition, results of laboratory studies provided by two
water treatment companies indicate that corrosion rates of less than
2 mils/yr can be achieved in such water. These data and information are
discussed below and in docket item IV-B-2.
Case history performance data were provided by four water treatment
companies on corrosion rates achieved at cooling towers that use water
with high chloride, hardness, and alkalinity levels similar to those cited
by the commenter. According to one company, corrosion is successfully
controlled with a nonchromate program in a CCT in Phoenix, Arizona, that
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uses makeup water similar to that cited by the commenter. The makeup
water has a total hardness level of about 176 to 192 ppm (60 percent
calcium hardness, 40 percent magnesium hardness), a chloride concentration
of about 132 to 148 ppm (equivalent to about 218 to 244 ppm NaCl), and a
pH of 7.8. The recirculation water has a total hardness of about 620 to
680 ppm and a chloride level of 480 to 556 ppm (about 790 to 920 ppm
NaCl). Based on these levels, the CCT operates with about 3.7 cycles of
concentration. Sulfuric acid is added to the recirculating water to
reduce the pH to about 7.0. Slowdown and chemical feed are controlled
automatically by a conductivity sensor, and acid feed is controlled
automatically by a pH sensor. This CCT has used an orthophosphate-based
treatment program with dispersants for several years. Corrosion rates as
measured with carbon steel coupons average 1 to 1.33 rails/yr with no
pitting. In addition, there has been no problem with deposition or
underdeposit corrosion in the system piping.
An ICT at a refinery in Kansas also uses water similar to that cited
by the commenter. The recirculating water has chloride levels of 400 to
800 ppm (660 to 1,320 ppm as NaCl) and total hardness levels of 1,000 to
1,500 ppm (calcium hardness accounts for about 40 percent of the total
hardness). A phosphate program has been used for the past 10 years. The
average corrosion rates as measured with carbon steel coupons have been
less than 1 mil/yr, and there have been no problems with deposition or
underdeposit corrosion in the system piping.
One of the case studies cited at proposal was for the CCT at a
shopping mall in Virginia. As noted in the proposal BID, the TDS level in
the makeup water for this CCT is significantly higher in the summer than
during the rest of the year. During the summer of 1986, the TDS level was
as high as 2,500 ppm; in other years, the summer average has been about
700 to 800 ppm. During the rest of the year, the TDS level is typically
300 ppm. Most of the additional dissolved solids in summer are NaCl from
seawater that enters the reservoir when the river flow is low. According
to one water treatment chemical distributor, corrosion rates measured on
carbon steel coupons average about 0.5 mil/yr during the summer. In
addition, operators indicated that the condenser tubes have been found to
be clean when checked each winter, and no problems with deposition or
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underdeposit corrosion in the system piping have been detected. A
phosphonate-based treatment program is used in this CCT.
An ICT at an ethylene production plant uses recirculating water with
a total hardness of 390 ppm, chloride concentration of 400 ppm (660 ppm as
NaCl), and a total alkalinity of 200 ppm. Carbon steel corrosion rates of
less than 1 rall/yr were measured in 60°C (140°F) return water, and no
fouling occurred in the plant heat exchangers. Because many dissolved
solids are less soluble at higher temperatures, the worst Ruling would be
expected to occur in the heat exchangers. The absence of deposition in
the heat exchangers suggests that the pipes are also clean. Corrosion is
controlled at this ICT using a zinc, inorganic phosphate, and organic
phosphate corrosion inhibitor program.
Two water treatment companies provided the results of laboratory
corrosion studies that evaluated water treatment programs under conditions
similar to those cited by the commenter. In one study, water circulating
through the test equipment had a total hardness of 400 ppm, a chloride
concentration of 412 ppm (824 ppm as NaCl), and an alkalinity level of
20 ppm. Average carbon steel corrosion rates of 0.9 and 1.2 mils/yr were
achieved using a high phosphate inhibitor at pH levels of about 7 to 8.
Average carbon steel corrosion rates of 1.1 and 1.2 mils/yr were achieved
using a molybdate/orthophosphate/azole blend at pH levels of about 7 to 8,
and no pitting was observed. The other study was conducted to evaluate
the same zinc, inorganic phosphate, and organic phosphate blend used in
the ICT at the ethylene production plant described above. The
recirculating water used in the laboratory had a total hardness of
1,350 ppm, a chloride content of 600 ppm (990 ppm as NaCl), and an
alkalinity level of 50 ppm. The corrosion rate achieved under these
conditions was 1.4 mils/yr, which is slightly worse than the 1 mil/yr
achieved in the ICT under better conditions. These similar results are in
contrast with the commenter's belief that corrosion rates achieved in the
field would be worse than those in the laboratory.
Two additional water treatment chemical distributors did not provide
site-specific data but indicated that their nonchromate treatment programs
can control corrosion in CCT's using water with high chloride, hardness,
and alkalinity levels. One distributor indicated that CCT's using makeup
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water with 200 to 400 ppm NaCl are easily treated with nonchromates even
if the water also contains high hardness and alkalinity levels. This
distributor also claims that nonchromate programs can be used successfully
in systems containing much higher NaCl levels (e.g., even in brackish
water that contains 20,000 to 40,000 ppm NaCl). The other distributor
stated that acceptable results (unspecified corrosion rates, but
<5 mils/yr) can be achieved with molybdate or all-organic programs.
However, if hardness levels are high, it may be necessary to add acid to
reduce alkalinity and to increase the level of dispersants to control
deposition.
To achieve acceptable results with nonchromates, the system must be
properly monitored, controlled, and maintained. Although operators may
not maintain and control system parameters properly, as suggested by the
commenter, it would not be because adequate programs or information about
proper procedures are unavailable. As shown above, the case history
performance data and other information obtained from the water treatment
companies show that acceptable corrosion rates of less than 2 mils/yr can
be achieved in CCT's and ICT's that use water with high chloride,
hardness, and alkalinity levels. These corrosion rates are comparable
with corrosion rates achieved in average water and are only slightly
higher than some of the rates reported by the commenter for chromate
programs.
2.1.8 Comment
One commenter (IV-0-27) noted that nonchromate programs do not
control microbiologically influenced corrosion (MIC) in corroded or
deposit-laden systems that use corrosive water. The commenter has
measured corrosion rates of 80 to 100+ mils/yr in carbon steel piping for
CCT's in New York City that were treated with molybdate and that also
suffered from MIC. These rates are not observed in CCT's treated with
chromates, and the commenter believes that the micro-organisms responsible
for MIC are controlled by the inherent toxicity of the chromates.
Response. Corrosion inhibitors are not designed to kill the
micro-organisms responsible for MIC; this is accomplished with biocides.
Because chromium is toxic, however, it may have some incidental biocidal
properties. Therefore, greater amounts of biocides may be required when a
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system Is switched to a nonchromate program. Regardless of the corrosion
inhibitor, MIC may occur if deposition is not controlled adequately
because blocides cannot penetrate the deposit to kill the micro-
organisms. As Indicated in the response to Comment 2.1.4, steps to
control deposition of suspended solids, such as modifying the water flow
or Installation of sidestream filters are available and easily
implemented. However, as described in the response to Comment 2.1.3, if a
system is already heavily corroded, it will need to be cleaned before
switching to nonchromates. In summary, EPA believes that MIC can be
controlled adequately in clean CCT systems by nonchromate treatment
programs with good control of deposition and appropriate supplemental
biodde programs.
2.1.9 Comment
One commenter (IV-F-1 [Seftonl) has performed research that shows
that chromates seem to inhibit algae growth, and many cooling tower
operators have found that they need little or no biocide with a chromate
program. Also, the commenter believes that old habits may be hard to
break and that many operators will not add sufficient biocide with
nonchromate treatment programs.
Response. Chromium compounds are sold for use as corrosion
inhibitors, not as biocides. However, because of the toxic properties of
chromium, chromate treatment programs may have some incidental blocidal
properties. Consequently, CCT operators may need to add greater amounts
of biocides when they switch to nonchromate treatment programs.
Typically, water treatment distributors recommend the amount of biocide
necessary with any type of treatment program. The recommended biocide
treatment should be incorporated into the CCT operators routine operation
and maintenance of the CCT. Installation of equipment to add biocides
automatically to the system would simplify the operators' work load.
However, the operators would still need to monitor the system periodically
(visually and/or chemically) to determine that biological growth is under
control.
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2.2 HEALTH EFFECTS/RISKS
2.2.1 Comment
Two commenters (IV-D-9 and IV-0-30) believe that the results of
chromium toxldty studies are not adequate to prove that the highly
soluble Cr"1"6 1n water treatment chemicals 1s carcinogenic. Both
commenters Indicated that many studies show only slightly soluble or
insoluble Cr"1"6 to be carcinogenic and that the carcinogenicity of soluble
Cr"1"6 shown in some studies may be overstated or the result of other
factors.
One commenter (IV-F-1 [Jones]) cited results of animal inhalation
studies that show that only calcium chromate produced a carcinogenic
response. Other Cr*6 compounds noted to be positive when implanted
intrabronchially or intratracheally include sodium bichromate, zinc
potassium chromate, zinc chromate, and strontium chromate. In one study
cited by the commenter, 20 Cr"1"6-containing compounds were administered
intrabronchially as pellets, and only the sparingly soluble materials
produced a carcinogenic response. The components that produced bronchial
carcinomas included strontium chromate, calcium chromate, and to a, lesser
extent, zinc chromate.
Response. The 1984 Health Assessment Document for Chromium (HAD)
(EPA 600/8-83-014F) describes both positive as well as negative studies on
soluble chromates.8""10 The experimental protocols used in these negative
studies were inadequate, and, thus, the negative findings are not adequate
to discount or negate the positive carcinogenic effect observed for
soluble chromates in the Steinhoff study. Also, since the time the HAD
was published, additional scientific evidence has demonstrated the
carcinogenic activity of soluble Cr"*"6 in exposed animals. Furthermore,
although human exposure data are insufficient to identify the specific
compounds involved in the etiology of lung cancer, recent studies have
also shown epidemiological evidence associating exposure to soluble Cr"1"
with an increased cancer risk.11"17
2.2.2 Comment
One of the commenters (IV-D-9) indicated that EPA's position on the
carcinogenicity of Cr+s conflicts with that in the 1985 National Institute
of Occupational Safety and Health (NIOSH) Pocket Guide for Chemical
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Hazards, which states that on the basis of current evidence, all Cr is
carcinogenic except for sodium, potassium, hydrogen, and lithium
•onochromates and dichromates. Furthermore, this commenter indicated that
the Agency for Toxic Substance and Disease Registry (ATSDR) concluded that
sodium dichromate was only a weak carcinogen under the test conditions in
the Steinhoff study.
Response. The EPA acknowledges that there are varying degrees of
scientific support associating an increased cancer risk with exposure for
the many chromium compounds. When EPA evaluated the scientific data, the
authors of the HAD took the position that it would be prudent to consider
all Cr+6 compounds to be carcinogenic given the available data as well as
the uncertainties in the data. The EPA's Science Advisory Board (a group
of nationally known scientists external to EPA and who give scientific
advice to EPA) stated that it "agrees with the position stated in the
draft document that Cr(VI) should be classified in Group 1 ('The chemical
... is carcinogenic to humans') of the criteria adopted by the
international Agency for Research on Cancer." Hexavalent chromium
compounds also are assigned a "high" hazard ranking for the purposes of
reportable quantity adjustments under the Comprehensive Environmental
Response, Compensation, and Liability Act. This ranking is based on a
potency factor of 389 (mg/kg/day)'1, determined from the Mancuso ^
epidemiological data, and a weight-of-evidence Group A classification.
A representative from NIOSH testified before the Occupational Safety
and Health Administration (OSHA) on August 1, 1988, on OSHA's proposed
rule on air contaminants that, based on evidence published since 1975,
NIOSH recommends that OSHA should consider all Cr*6 compounds as
19 20
occupational carcinogens. »
The ATSDR document referenced by the commenter on chromium was still
in draft form. The EPA has commented to ATSDR that EPA and NIOSH
(according to the NIOSH testimony) consider all Cr+s compounds to be
carcinogenic and that ATSDR should consider changing its conclusions in
the draft document. As of the time of this comment response, the document
is still in draft form.
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2.2.3 Comment.
One commenter (IV-D-30) indicated that the International Agency for
Research on Cancer (IARC) concluded that the carcinogenic effect in the
Steinhoff study was weak.8 This commenter notes that EPA cites the
Steinhoff et al.t report as the basis for its position but fails to report
other animal studies that have shown negative results with respect to the
causation of lung cancer.21"23 Considering the weight of these other
studies, the commenter says it is quite possible that the Steinhoff
et al., method of applying the chromate dosages actually "duplicated more
the functional mechanism of the sparingly soluble salts, than it did to
prove the carcinogenicity of the water soluble compounds." The commenter
notes that the carcinogenic effect was weak; all tumors developed at the
end of the lifetime study, and none was the cause of death.
Response. The EPA agrees that the IARC monograph is a valuable
resource material. The EPA has referenced IARC monograph Volume 23, 1980
in the HAD on chromium (1984). The HAD, however, contains studies on Cr+6
that were not referenced by the IARC working group in their evaluation of
8 9 23
the carcinogenic effects of chromium compounds in 1980. • » The
Steinhoff et al., study was not cited by IARC in the 1980 (Vo-lume 23)
monograph.
Regarding the method of applying dosages, although it would be
desirable to exactly mimic the human exposure route via an inhalation
study, the intratracheal instillation method of exposure used by Steinhoff
is relevant to the human exposure route in that it is in the respiratory
tract and is useful in the qualitative assessment of carcinogenicity.
Despite the fact that the tumors did not kill the test animals, the test
substance did result in a positive carcinogenic response in this study.
2.2.4 Comment
One commenter (IV-D-9) believes that the carcinogenic effects
observed in the Steinhoff tests may not be transferable to humans because
the intratracheal administration of treatment method used in that study
does not reproduce the human exposure route of inhalation.
Response. Although experiments that actually duplicate the human
route of exposure are preferable over those that do not, EPA believes that
positive results achieved by different routes of exposure should not be
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discounted. As stated in the response to Comment 2.2.3, the intratracheal
instillation method of exposure is relevant to the inhalation pathway. It
is difficult to design experiments that exactly duplicate the human
exposure scenario with animal models due to numerous factors such as
doslmetric differences in the respiratory tract between rodents and
humans. The EPA determined the Steinhoff study to be an acceptable
protocol and useful in the qualitative assessment of cardnogenicity.
Other studies were used in the overall weight of evidence conclusion that
all Cr+6 compounds should be considered carcinogenic. These include
epidemiology studies, animal studies, and in vitro studies (including
mutagenicity studies). These are summarized in the HAD.
2.2.5 Comment
One commenter (IV-D-30) cited epldemlological studies of chrome
plater and chromium production workers exposed to a mixture of chromates
that showed no higher mortality for these workers than for the general
population. 16»21* Furthermore, the commenter indicated that most of the
epidemlological studies, including the Mancuso study, did not consider the
effects of cigarette smoking, radon, or other occupational exposure
factors that are known to affect the incidence of lung cancer. The
commenter also quoted the following IARC conclusions on chromium
carcinogenicity that were reported in the IARC Monographs, Volume 23,
1980:
There is sufficient evidence for the carcinogenicity of calcium
chromate and some relative insoluble chromium [VI] compounds
(sintered calcium chromate, lead chromate, strontium chromate,
sintered chromium trioxide, and zinc chromate) in rats. There is
limited evidence for the carcinogenicity of lead chromate [VI] oxide
and cobalt-chromium alloy in rats. The data were inadequate for the
evaluation of the carcinogenicity of other chromium [VI] compounds
and of chromium [III]) compounds. There is sufficient evidence of
respiratory carcinogenicity in men occupationally exposed during
chromate production. Data on lung cancer risk in other chromium-
associated occupations and for cancer at other sites are
insufficient. The epidemiological data do not allow an evaluation of
the relative contributions to carcinogenic risk of metallic chromium,
chromium [III], and chromium [VI] or of soluble versus insoluble
chromium compounds.
In addition, the commenter quoted the following conclusion from lARC's
Environmental Carcinogens Selected Methods of Analysis (1986):
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The epidenriological data do not permit an evaluation of the effects
of CrflllJ versus Cr[VI] or the role of solubility, nor can the
ultimate carcinogenic form of Cr or a dose-response relationship be
determined from these studies. There is no definite evidence that Cr
caused cancers other than in lung, although excesses of cancers of
the esophagus, stomach, pancreas, maxillary sinus, and prostate have
been reported in some studies (IARC, 1980; Sheffet et al., 1982).
Response. The overall mortality ratio was actually less than 1
(0.92) in the Hayes et al., study.2" (A standardized mortality ratio is
calculated by dividing the observed number of deaths .by the number
expected.) This observation is consistent, however, with what is known as
the "healthy worker" effect. That is, workers will tend to be healthier
than the general population by virtue of being in the work force and thus
will have lower overall age-adjusted mortality rates. This does not
negate a specific effect such as an elevated risk for lung cancer.
According to the epidemiological criteria, the strength of the
association between chromium exposure and lung cancer is strong and that
it is unlikely that confounding would have played a significant role in
the results that have been observed. There is a consistency of results
found by different investigators in different countries, a dose-response
and high lung cancer mortality ratios observed in several studies, and a
specificity of tumor site (lung). With regard to smoking per se as a
confounding factor, assumptions and modifications were made in the dose-
response assessment in the chromium HAD (1984) that demonstrated that
smoking as a confounder would not have significantly affected the dose
response assessment. (Refer to the HAD for more detailed information in
this matter.) Radon exposure is not known to be present in chromate
production or other industrial settings where chromium compounds have been
studied epidemiologically.
The EPA agrees that alone, the epidemiological data do not allow a
firm conclusion to be drawn regarding the association between one oxida-
tion state or soluble versus insoluble compounds and the causation of lung
cancer among workers. The EPA's conclusions about the carcinogenicity of
Cr compounds are based on the weight of evidence from epidemiological
studies plus long term animal studies and short-term bioassays.
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2.2.6 Comment
One commenter (IV-D-30) believes that the following statement in the
preamble concerning estimation of the Cr+6 potency factor from the results
of the Mancuso study is Incorrect: "Although there is the possibility of
a slight underestimation of exposure prior to 1949, which would decrease
somewhat the potency factor, there are other factors that may have
resulted in an increased potency estimate." The commenter believes that
underestimating exposure in an epidemiological study will result in a
perceived increase in apparent potency, not a decrease. The commenter
also notes that this study involved exposure to a mixture of insoluble,
slightly soluble, and soluble chromates and, thus, it cannot be used to
calculate the risk of exposure to soluble Cr1"6 (the water treatment
variety) alone.
Response. In the 1984 HAD for chromium (page 7-105), it is clearly
stated that risk may be overestimated because there is the possibility
that the use of 1949 hygiene data, may result in some degree of
underestimation of worker's exposures. Note the following excerpt taken
from page 7-105 of the HAD.
Thus, a cancer risk estimate based on total chromium exposure will
underestimate the risk due to hexavalent chromium alone. In the
Bourne and Yee (1950) study, the ratio of trivalent (Cr III) to
hexavalent (Cr VI) chromium in the airborne dust in the plant's nine
major departments ranged from 1 to 3, except in the case of two
departments, where the ratios were 6 for the lime and ash operation
and as high as 52 for the ore preparation operation. Therefore, the
ratio of trivalent and hexavalent chromium in the plant did not
exceed 52, seems unlikely to exceed 6, and may be smaller. Thus, the
underestimation of the risk from hexavalent chromium when the Mancuso
(1975) data on exposures to total chromium are used is unlikely to be
more than sevenfold, if the ratio is assumed to be 6. There are two
other factors, however, that may result in an overestimation of the
risk: (1) there is a possibility that the use of 1949 hygiene data
may result in some degree of underestimation of worker's exposures,
and (2) the risk presented in this report may be somewhat
overestimated because of the implicit assumption that the smoking
habits of chromate workers were similar to those of the general white
male population. It is difficult to determine how much the risk has
been overestimated in this regard. However, it seems reasonable to
assume that the risk is not overestimated by more than 4 times on the
assumption that 80 percent of the chromium workers and 50 percent of
the control population smoked cigarettes, and that the exposure may
be underestimated by a factor of 2.
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The above assumption about the smoking incidence may overestimate the
risk because 1t is highly probable that the smoking incidence was greater
in the chromate industry population than in the general population.
Overall, EPA's Human Health Assessment Group believes that the extent of
risk underestimation and overestimatlon was approximately equal.
Furthermore, pulmonary chromium levels were elevated in autopsied samples
of exposed workers who had died from lung cancer 15 to 195 months after
their chromium exposure, implicating chromium as an etiological agent in
the cause of death.
The EPA prefers to use epidemiological data to derive potency
estimates rather than animal data. Although there are uncertainties in
the exposure assumptions made, EPA believes in the absence of better
information, the assumptions described above are reasonable.
2.2.7 Comment
One. commenter (IV-D-28) believes that a threshold concept for Cr*6
carcinogenicity is scientifically valid. This belief is based on many
individual findings published or presented recently that together have
resulted in a postulated mechanism for cancer induction. These findings
indicated that only soluble and slightly soluble forms of Cr"1"6 can
potentially enter cells, that the body has several defense mechanisms
against Cr+6, and that Cr"*"6 must be reduced close to the deoxyribonucleic
acid (DMA) to produce DMA adducts capable of producing gene mutations.
The commenter indicated that the body defenses against Cr"1"6 begin at
inhalation. Particle size determines the amount of Cr"1" that is available
to the lungs. Various studies have shown that about 5 to 20 percent
reaches the lungs and that the rest is cleared and swallowed. Gastric
juices efficiently reduce Cr"*"6 to trivalent chromium (Cr"1"3), and
secretions in the lung have the capacity to reduce some of the Cr"1"6 that
enters. Secondary defense is played by the pulmonary alveolar
macrophages, which physically reduce Cr+s by engulfing it and by
enzymatically reducing it to Cr"1"3. In addition, up to 2 milligrams (mg)
of Cr"1"6 absorbed by the blood can be reduced to Cr"1"3 by plasma. Any Cr+s
that enters a cell can be reduced by electron donors in the mitochondria
and by enzymes in the microsomes, cytosol, and other cellular organelles.
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The concenter also suggested that if the Cr+ gets past these
defenses, it may reach the DMA. Several theories have been suggested to
exDlaln how the Cr+6 Interacts with DNA. Although the mechanism is
e , is known that the Cr>° must be reduced either close to the DNA
or afte; it is incorporated into DNA because Cr+3 is detected in DNA an
has been shown to be active with ONA. Once a DNA adduct is produced the
!ast line of defense is the DNA repair process by various enzymes. In
humans, this defense is good. However, if not repaired, the modified ONA
molecule would have the potential to produce mutations. A mutation
produced during reproduction of the cell would then have the potential to
be cancerous. Although the reduction capacity of the body cannot be
precisely quantified, the commenter estimated that it is approximately
100 times or more than that needed for low-level workplace exposures.
Resp0nse. The EPA agrees with the commenter that the body has some
defense mechanisms to protect against toxic effects of exposure to
chromium compounds. These mechanisms include: (1) clearing and
swallowing large particles containing Cr+6 reduces th^amountjf chromium
available to the lung; (2) effective conversion of Cr to Cr by the
gastric juice, lung secretions, blood, and intracellular organelles
(cytosol, mitochondria, and microsomes); and (3) physical reduction of
Cr+6 by pulmonary alveolar macrophages that engulf it. However, wide
intraspecies and interspecies variations and a host of other factors
generally affect pharmacokinetics and metabolism of the chromium
compounds. In spite of all these protective mechanisms, Cr can reach
target molecules and induce the carcinogenic process at some dose levels
as seen in human and experimental animals.
The commenter mentioned that only the soluble and slightly soluble
forms of Cr+6 can enter the cell and that the insoluble forms cannot. In
contrast, EPA believes that even the insoluble compounds can be made
bioavailable because body organ systems have a capacity to disintegrate
and dissolve insoluble chromium compounds and thereby enter the cell.
The genotoxicity of chromium and its compounds has been studied
extensively. The chromium compounds have been evaluated in 315 short-term
tests. Hexavalent chromium has produced positive responses in most of the
test systems used to investigate its potential for mutagenicity. To
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express the positive mutagenic response, Cr+s must enter the cell nucleus
in order to interact with DMA and produce a ONA adduct or DMA damage.
Hexavalent chromium compounds have been classified as human
carcinogens based on human epidemiologic studies supported by experimental
animal studies and in vitro tests with submammallan test systems.
However, for practical and statistical reasons, cancer risk associated
with the low level exposure cannot be measured directly either by animal
experiments or by epidemiologic studies. Therefore, EPA must depend on
the current understanding of the mechanism of carcinogenesis. At the
present time, the dominant view of the carcinogenesis process involves the
concept that most cancer-causing agents also cause irreversible damage to
DMA. This position is reflected by the fact that a very large proportion
of agents, including Cr"1"6, that cause cancer are also mutagenic. There is
reason to expect that the carcinogenic response, which is initiated by a
mutagenic event, is of a nonthreshold nature and thus can be associated
with the linear nonthreshold dose-response relationship. Therefore, the
hypothesis that was developed by the commenter cannot be considered
adequate to establish the existence of a threshold when mutagenic
responses are noted to occur.
2.2.8 Comment
One commenter (IV-D-28) cited recent reviews of the epidemiological
data that indicate chromate-induced lung cancers are the result of the
alkaline process used before 1961 in the production of sodium bichromate
and chromic acid or in certain chromate pigment manufacturing opera-
tions. Since 1961, process changes have been implemented, industrial
hygiene practices have been improved, and the workplace exposure limit has
been set at 0.05 milligrams per cubic meter (mg/m3) in the United
States. Because studies of epidemiological data obtained in the last
25 years have not noted an increased incidence of lung tumors, the
commenter believes that the current workplace exposure limit is a safe
level.
Response. It is unlikely that cancer epidemiologic studies of
chromate manufacturing workers employed since 1961 would have a sufficient
length-of-followup to detect a statistically significant excess risk of
lung cancer. Furthermore, epidemiologic studies of chromium-exposed
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workers who did not experience an "alkaline process" (e.g., chrome
platers) still found those workers to have an excess risk of lung cancer.
2.2.9 Comment
One commenter (IV-D-30) believes that the scientific basis for
inferring human cardnogenicity from mutagenicity in rats and bacteria is
weak and that the EPA proposal fails to indicate that studies have shown
an extraordinary number of common food products contain natural chemical
compounds that also have been shown to be carcinogens and mutagens.25
Based on these studies, the commenter concluded that an individual is
exposed to a much greater risk from food than from cooling tower drift.
Furthermore, the commenter indicated that studies have shown that workers
exposed continuously to relatively high levels of chromate can experience
severe ulceration of the skin and nasal mucosa but that none of the
lesions has been shown to become cancerous.
Response. The evidence is strong showing an association between
exposure to chromium compounds and lung cancer. This conclusion is based
on numerous epidemiological studies with workers and is supported by
multiple positive animal studies and mutagenicity tests as summarized in
the HAD. The EPA agrees that there are naturally occurring carcinogens,
as well as man-made, and that some of these can be found in food. The EPA
in this rulemaking is concluding that exposure to CCT drift is significant
enough to warrant regulation under TSCA Section 6. Whether the risk is
greater than or less than risks from other sources, such as food intake
does not enter into this decision.
Exposure to some chromium compounds at high enough concentrations can
result in dermatitis and effects on the respiratory tract in addition to
lung cancer. The fact that skin and nasal mucosal effects have generally
not become cancerous does not preclude one from getting lung cancer or
alter conclusions from the many studies that show the association between
chromium exposure and lung cancer.
2.2.10 Comment
One commenter (IV-0-29) believes that EPA has seriously overstated
the potential risk of Cr"1"6 emissions from CCT's. The commenter (IV-D-29)
has taken air samples near cooling towers using chromate treatments and
analyzed them for Cr+5. None of the samples contained detectable
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concentrations of Cr"1" , and concentrations were well below the OSHA
exposure standard of 0.5 mg/m3 and the American Conference of Governmental
Industrial Hygienists (ACGIH) threshold limit value (TLV) of 0.05 mg/m3.
Swipe and soil samples also were taken at random locations near the
cooling tower, and no indication of fallout of Cr+6 particulates was
indicated. The soil samples contained 9.6 to 32.5 micrograms of total
chromium per gram of soil (wg/g) but contained less than 0.1 ug/g of
Cr+6/g soil. Swipe samples showed 0.0050 to 0.235 milligrams (mg) of
total chromium per filter and a maximum of 0.0055 mg Cr+6/filter.
Response. The fact that the monitored values are below occupational
standards does not mean that there is no significant health risk. The
EPA's concern is with all members of the general population, including
sensitive subgroups, who may be continuously exposed to toxic air
pollutants 24 hours per day, 7 days per week over a lifetime. In
comparison, OSHA's standards are designed to protect "healthy" workers
from exposures of 8 to 10 hours per day, for 5 days per week. The EPA's
estimates of exposure were based on dispersion modeling and assumptions
regarding emission rates, meteorology and population. The maximum annual
average concentration of Cr"1"6 estimated from a large model CCT was
0.0055 wg/m3. It is possible that the impact from the cooling tower
mentioned by the commenter is below the limit of detection for the
monitoring method used. There are several technical problems commonly
encountered in monitoring Cr*6 in the ambient air (and in soil) including
conversion of Cr"1" to Cr+ in the sampling equipment and with the
detection limit being too high for the various methods in use. The
concentrations reported by the commenter are not inconsistent with
estimates developed by EPA using dispersion modeling techniques. For a
more detailed discussion of how the risk estimates were developed, the
commenter should refer to Appendix B of the proposal BID.
2.2.11 Comment
One commenter (IV-0-30) indicates that EPA has overestimated the
effects from exposure to other hazards such as asbestos, arsenic, dioxins,
and methylene chloride by a factor of 10 or more in the past. Conse-
quently, the commenter believes that risk from Cr+s could be overestimated
by at least a factor of 10. Application of this overestimation factor to
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the risk of exposure to Cr"1"6 emissions from CCT's would result in a more
"realistic" number of lung cancer incidences (0.4 to 11.2 cases per
year). The commenter concludes by saying that In either case, the number
of cancer cases attributable to exposure to chromate in cooling tower
drift 1s very small compared to the nearly 150,000 cases of lung cancer
annually—80 to 90 percent of which are thought to be caused by cigarette
smoking.
Response. The EPA notes in Appendix B of the proposal BID that there
are uncertainties in the risk analysis which could result in either an
underestimate or overestimate of the risk from CCT's. There are
uncertainties in all elements of any risk assessment including the potency
estimate, the estimates of exposure, the emissions estimates and all the
assumptions used in each step of the process. Some of the uncertainties
in assumptions used may tend to overestimate risk, while others used may
underestimate risk. The basis for the commenter1s conclusion that EPA
overestimates risk by a factor of 10 is unclear. The EPA believes the
estimates presented 'are reasonable given the uncertainties in the
available Information and the technical "tools" available to conduct the
risk assessment. The fact that exposures to other toxicants in one's
environment may result in a greater risk than from Cr+s emissions from
CCT's does not negate the findings of this analysis or the need for this
regulation.
2.2.12 Comment
One commenter (IV-D-24) believes that prohibition of Cr+6-based water
treatment chemicals may create a potential health hazard from
proliferation of biological organisms that far outweighs the risk from
Cr*6. The commenter believes that chromate programs effectively control
many potential health risks from biological organisms, but that the same
results may not be achievable with nonchromate programs.
Response. Upon reviewing a significant amount of scientific
literature, the only harmful biological organisms that appear to be
associated with cooling tower emissions are Legionella pneumophila.
bacteria responsible for what is commonly referred to as Legionnaire's
Disease. These bacteria are found in many water sources including surface
water supplies. Several biocides (e.g., chlorine and quaternary ammonium
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salts) are sold as part of regular treatment programs for controlling
these organisms. Chromium compounds are sold for use as corrison
inhibitors, not as biocides. However, because of the toxic properties of
chromium there may be some incidental biocidal properties. If readily
available biocidal treatment agents are used at concentrations recommended
by the manufacturer, growth of biological organisms such as Legione11a
pneumophila is expected to be minimal and increased outbreaks of disease
are not expected to occur as a result of this rulemaking.
2.2.13 Comment
One commenter (IV-F-1 [Sefton]) believes that the proposed rule may
cause health hazards to increase as greater amounts of biocides such as
isothiazolin or 2,2-d1bromo-3-nitr1lo propionamide (DBNPA) are emitted
from CCT's. Even with additional biocides, the commenter believes that
biological growth is nourished by many of the alternative programs and
that harmful organisms such as Legionella pneumophila are being propagated
and dispersed.
Response. Since the majority of CCT owners in the United States
already use alternative treatment programs, EPA does not believe that
because of this regulation health hazards will increase significantly by
the increased use of biocides (which are currently regulated by EPA's
Office of Pesticide Programs). Scientists from the Center for
Communicable Disease Control have indicated that there should not be any
increase in outbreaks from Legionella pneumophila if cooling towers have
been treated properly with a biocidal regimen.
2.2.14 Comment
One commenter (IC-F-1 [Sefton]) believes that health risks could
increase for some elderly residents of condominiums in Florida if they are
without air conditioning while failed CCT system components are
replaced. The commenter believes that piping and other components in CCT
systems using water containing high chloride, hardness, and alkalinity
could fail after switching to nonchromate treatment programs and that
repairs would require extended downtime (see Comment 2.1.7).
Response. As indicated in the response to Comment 2.1.7, acceptable
corrosion rates are achieved with several nonchromate treatment programs
in CCT's using the poor quality water cited by the commenter. Therefore,
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properly operated and maintained CCT's are not expected to experience an
interruption in air conditioning service to replace corroded components.
2.3 REGULATORY APPROACH
2.3.1 Comment
Two commenters (IV-D-25 and IV-0-31) Indicated that proposal of a
rule under Section 6 of TSCA triggers automatic export notification
requirements under TSCA Section 12(b) for the regulated chemical. One of
the commenters (IV-0-31) also indicated that EPA's interpretation of the
TSCA requirements is that they apply to chemicals subject to the
triggering regulations rather than to such chemicals in restricted uses.
Consequently, under the proposed rule, export notices would be required
for any substance or mixture containing Cr+s, regardless of its nature or
intended use. Both commenters believe that the rule should be changed to
limit the circumstances that would require export notifications. One
commenter (IV-0-31) believes EPA should either restrict the category of
chemicals covered by the proposed rule or specify the category of
chemicals in the rule for which export notice is required. The other
commenter (IV-D-25) requested that the final rule specifically exempt
paint and coatings manufacturers, or their pigment suppliers, from the
export notification requirements because they would be unduly burdened by
these requirements.
Response. Section 12(b) of TSCA requires that any person who exports
or intends to export to a foreign country a chemical substance or mixture
for which a rule has been proposed or promulgated under Section 5 or 6 must
notify EPA of such exportation or intent to export. The Administrator is
then required to furnish notice of the rule to the government of the
country receiving the export. Because the chemical substance subject to
this rule is Cr"1" , the commenter is correct in noting that export notices
would be required for any substance containing Cr"1"6, not just for
Cr"1" -based water treatment chemicals. It is not clear that this require-
ment could be narrowed, as a practical matter, because of the inability to
determine the possible end use of the material at the time of export.
The EPA anticipates that the burden of the export notification
requirements will be minimal and has incorporated this into the overall
estimated cost for industry to comply with the labeling, reporting, and
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recordkeeping requirements (see response to Comment 2.5.8). Companies are
required only to provide notification the first time they export or intend
to export to each country in a calendar year. The notification consists
of the company's name and address, chemical name, TSCA section that
triggered the notification (Section 6 in this case), countries that are
the receivers, and the export date or intended export date.
2.3.2 Comment
One commenter (IV-D-31) believes that EPA should narrow the scope of
application of the proposed rule. In the preamble to the proposed rule,
EPA stated that the intent of the rule is to regulate the use of Cr*6 in
CCT's by controlling the use of Cr"1"6, usually in the form of sodium
dichromate. Thus, the rule would apply to any compound containing
chromium in an oxidation state of six, regardless of the nature of the
substance or its uses. The commenter concluded that EPA did not intend to
include such substances as lead chromate (a yellow pigment widely used for
highway markings) in the scope of the rule. The commenter suggested that
the scope of the rule should, therefore, be narrowed to include only those
substances that may reasonably be used in CCT's. Even if EPA does not
narrow the scope of application of the rule, as a matter of policy, the
rule should contain a list of the chemicals covered by the rule. This
would enable those persons who are potentially subject to the rule to
verify their status and, thus, would provide a higher level of
compliance.
Response. Section 6 of TSCA states that when use of a chemical
substance presents an unreasonable risk to human health, a rule may be
promulgated under Section 6 that protects against the risk by prohibiting
the distribution in commerce of such substance for a particular use and/or
by prohibiting any manner or method of commercial use of such substance.
The EPA has determined that inhalation of Cr"1"6 emitted from CCT's presents
an unreasonable risk to human health. The proposed rule was developed to
protect against this risk and specifically prohibits only the distribution
in commerce of Cr+°-based water treatment chemicals for use in CCT's and
the use of these chemicals in CCT's. These requirements were stated
clearly in section 249.68(c) of the proposed rule (the "Applicability"
section). With the exception of export notification requirements for any
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Cr"1"6 chemical, substances containing Cr4" for other uses are not covered
by the rule. (Discussion of the export notification requirements is
included 1n the response to Comment 2.3.1). Consequently, EPA believes
there is no need to identify specific Cr*6 chemicals covered by the rule.
2.3.3 Comment
One commenter (IV-0-29) recommended that the final rule be phased in
over a longer period than 120 days. The commenter stated that if EPA were
to identify a target year in which such a ban were to be in place, plans
could be made to replace critical equipment and begin conversion to
alternative chemicals in existing towers. All new towers could be
designed to not use chromates. At a minimum, the commenter recommended
that the rule contain a variance provision that would allow facilities
sufficient time to make any necessary regulatory arrangements and to
perform any required engineering modifications. For example, the
commenter operates a blowdown pretreatment facility to comply with the
discharge requirements of the local POTW. Any significant change in the
current operating procedure (e.g., a change in effluent composition) would
impact that agreement, and the commenter believes a1! required arrange-
ments for the new conditions with the POTW could not be completed within
120 days. In addition, if the current pretreatment system must be
modified (e.g., for reduction of phosphates), the commenter also believes
that the required design and engineering work could not be accomplished
within 120 days.
Response. The prohibition on the use of Cr* -based water treatment
chemicals in CCT's becomes effective 135 days after the date of publica-
tion of the final rule. The EPA believes this allows sufficient time for
CCT owners and operators to exhaust supplies of Cr"l"6-based water treatment
chemicals and complete the transition to the use of a nonchromate
program. Furthermore, the commenter and others aware of EPA's proposed
rule could begin the- transition long before publication of the final
rule. The EPA also is not aware of POTWs that impose restrictions on
phosphate discharges, but several POTW's have indicated that they do not
impose restrictions.27"29
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2.3.4 Comment
One coiranenter (IV-D-34) believes that the effective date of the
regulation is August 1, 1989, and noted that this date is during the
middle of the cooling season. The commenter suggested that a more
realistic effective date would be the end of the cooling season such as
December 1, 1989. At this time of year, the vast majority of cooling
towers will be emptied for the winter anyway. In contrast, another
commenter (IV-0-33) is concerned that the effective date of the regulation
will occur during the winter. The commenter notes that many small CCT
owner or operators who do not have information on the pending restrictions
would be faced with a 6-month or more supply of Cr"f6-based water treatment
chemicals that would have to be disposed of as regulated materials. The
commenter suggested that owners/operators be allowed to use Cr"1"6 materials
on hand at the effective date, but that no additional Cr"1"6 materials could
be purchased.
Response. The first commenter implies that it will be necessary to
shut down CCT's for cleaning in order to convert to nonchromate systems.
However^ in properly maintained systems, the existing chromate program is .
designed to prevent development of conditions that would require downtime
for cleaning, such as significant scaling or corrosion. Therefore, EPA
believes that the time of year that the regulation becomes effective is
not a concern. (See the response to Comment 2.1.3 for more information on
cleaning of CCT systems.)
The concern that owners/operators will be left with unusable
stockpiles of Cr"1"6 chemicals is not justified. The relevant trade
associations, publications and, most importantly, vendors of water
treatment chemicals are aware of the restrictions posed by the rule and
the effective date of the rule. In fact, vendors began making CCT users
aware of the upcoming prohibition of Cr"1"6 in CCT's as soon as the rule was
proposed in the Federal Register. No reputable vendor would sell a
customer a large stockpile of Cr"1"6 chemicals in the face of the pending
restrictions, and trade associations and publications will have extensive
opportunity to educate CCT users about the rule. Allowing CCT owners/
operators to use up existing supplies of Cr"1"6 chemicals as suggested by
the commenter could significantly delay the environmental benefits of the
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rule if large quantities of Cr+6 have been stockpiled, intentionally or
otherwise. For these reasons, no change to the effective date of the rule
has been made.
2.3.5 Comment
Twolo^enters (IV-0-24 and IV-D-27) believe that high-efficiency
drift eliminators (HEDE's) present a viable and technologically sound
alternative to prohibiting the use of chromates in CCT's and that the use
of HEDE's would alleviate health risks and make corrosion protection
economical and practical. One counter (IV-D-27) recommended that the
proposed rule be revised to include the option of installing HEDE's.
Response. The EPA considered the use of HEDE's as a regulatory
alternative during development of the rule. Drift eliminator
manufacturers indicate that HEDE's can remove up to 80 to 90 percent of
the drift discharged from lower efficiency drift eliminators (LEDE's).
Emission tests sponsored by EPA show that this range is an upper bound to
the effectiveness of HEDE's over LEDE's.
The lower effectiveness of HEDE's (approximately 85 percent) compared
.to a nonchromate alternative (100 percent emission reduction) is only.one
reason why the use of HEDE's is not the preferred alternative. The
nationwide costs of using HEDE's are estimated to be about $25 million
compared to $20 million for the nonchromate alternative. This deference
is due to the fact that HEDE's are not used widely in CCT's at present,
and the industry would incur significant capital costs to install them.
Also, the cost to develop a nationwide certification program for HEDE
efficiency and perform annual inspections would be approximately
$14 4 million or 60 percent of the nationwide costs of HEDE's. Because of
the large number of CCT's using chromates relative to the number of water
treatment vendors, the enforcement burden would be much greater for the
HEDE alternative than for the nonchromate alternative.
Because of the costs to retrofit, difficulties in implementation, and
the smaller emission reduction potential, EPA has concluded that the use
of HEDE's is not a feasible control alternative. Therefore, thejinal
rule does not allow the option of installing HEDE's to reduce Cr+
emissions from CCT's.
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2.3.6 Comment
One commenter (IV-F-1 [Jones]) believes that EPA does not have the
authority under TSCA to prohibit the use of Cr"1"6 compounds in CCT's
because: (1) TSCA requires that action be taken under other authorities
unless it is in the public interest to protect against risk under TSCA,
and a court decision (SEP. Inc., v. City of Dayton, 519.F. Supp^ 979,
989-90 [S.D. Ohio, 1981]) has upheld this TSCA requirement; (2) there is
clear authority under the Clean Air Act (CAA) to protect against the risk
of Cr"1"6 air emissions, the only media in which Cr"1"6 poses a risk; and
(3) the justifications for using TSCA rather than the CAA do not meet the
"public interest" criterion set forth in Section 6(c) of TSCA (i.e., the
incremental benefit for EPA's enforcement office is not sufficient to show
that regulating under TSCA is less costly and more efficient than
regulating Cr"1" emissions under the CAA). The commenter states that
prohibiting the use of a substance is a drastic measure, only to be taken
as a last resort when other authorities under which regulations could be
developed would not be adequate to address the risk from the substance.
The CCT regulation addresses only air emissions of Cr*6, and EPA has
already taken steps under the CAA towards regulating air emissions of
Cr*6. Also, EPA has stated that recordkeeping under the CAA would be
adequate. Consequently, the commenter believes that regulations.should be
developed under the CAA to protect against the risk posed by Cr*
emissions, possibly by setting a zero emission standard as EPA suggested
in the notice of the proposed TSCA rule.
Response. The EPA disagrees that its finding fails to satisfy the
"public interest" criterion in Section 6(c) of TSCA. The decision to
regulate Cr+s under TSCA rather than the CAA is a decision which is wholly
left to the discretion of the Administrator. After considering the
factors in section 6(c), EPA believes that the decision to use TSCA in
this rulemaking is a reasonable one and that adequate rationale for that
decision is presented in the Federal Register notice of the proposed rule
(53 FR 10206).
The decision cited by the commenter (SEP, Inc., v. City of Dayton)
involves the issue of whether the TSCA PCB regulations preempt (under TSCA
Section 18) State laws that are promulgated to control PCB's. The issue
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in that case is unrelated to the question of the relationship of TSCA to
other Federal laws administered by EPA. Although the Court in SEP
discusses TSCA Section 9, it did not reach a decision which would be
controlling in the present rulemaking. Section 9(b) of TSCA explicitly
states how the Administrator must resolve issues involving the
relationship of TSCA to other EPA statutes. As stated previously, EPA has
determined under TSCA Section 9(b) that it is in the public interest to
use TSCA to protect against the risks from the use of Cr+6 in CCT's.
In conclusion, EPA has reviewed the options for limiting exposure to
Cr"1"6 emissions from CCT's and has concluded that the reduction in risk to
the public and enforcement of the rule for this substance cannot be
satisfactorily accomplished in any way other than by prohibiting the use
of Cr"l"6-based water treatment chemicals in CCT's and the distribution in
commerce of these chemicals for use in CCT's.
2.3.7 Comment
One commenter (IV-F-1 (Seftonj) believes that the benefits of
chromate far outweigh its environmental problems and that the probable
consequences of the proposed rule are severe. Consequently, the commenter
believes that a more reasonable regulatory approach and one that would be
more beneficial to the public than the proposed rule would focus on
education of vendors, users, and cooling system design engineers. The
commenter suggested several aspects of this approach. First, an allowable
threshold level of Cr"1"6 could be determined. Second, using probable and
realistic human intake values, average distances from CCT's where Cr"1"6
concentrations exceed the allowable threshold could be determined. If the
concentrations within areas frequented by people are too close to the
threshold to protect human health, installation of HEDE's could be
required. This requirement would have the added advantage of minimizing
airborne dissemination of Legionella pneumophila, possibly by an amount
similar to the 85 percent by which health risks from chromium would be
reduced. Labels could be required on cooling water products indicating
that prolonged breathing of cooling tower mist containing the product
could increase the risk of lung cancer. Finally, maintenance people could
be "cautioned" to wear a dust mask when working in or around a cooling
tower containing chromium.
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Response. The EPA evaluated two regulatory alternatives:
(1) prohibition of the use of Cr+6, and (2) installation of HEDE's.
Prohibition of Cr"1"6 use was selected as the regulatory approach because it
is the most protective of public health and the costs are reasonable.
Furthermore, as described in the proposal BID, effective alternative water
treatment programs are readily available and are already in use at 75 to
90 percent of CCT's.
The EPA disagrees with the commenter's assertion that the benefits of
chromate far outweigh its environmental problems. As discussed at
proposal, EPA believes that continued use of Cr+6-based water treatment
chemicals in CCT's presents an unreasonable risk of injury to human
health. Hexavalent chromium has been determined to be a potent human
carcinogen and, as indicated in the response to Comment 2.2.7, the
carcinogenic response is of a nonthreshold nature. The average annual
exposure to Cr"1"6 emissions from CCT's is estimated to be about
140 mg/person (3.1x10" Ib/person), and the annual incidence of lung
cancer is estimated to be about 20 cases based on EPA's "best-estimate"
emission factor. (See docket item IV-B-5 for a detailed discussion of the
rationale and basis for the best estimate emission factor.) Additionally,
the available information indicates that a lower (and, in most cases, much
lower) public health risk results from exposure to chemicals used in
alternative water treatment programs.
The EPA also believes that the benefits provided by chromate can be
achieved with nonchromate treatment programs at reasonable cost. As
described in the proposal BID and in the responses to Comments 2.1.6 and
2.1.7, acceptable corrosion rates can be achieved with nonchromate
treatment programs. As indicated in the response to Comment 2.5.1, the
cost of prohibiting Cr"1"6 use in CCT's has been reestimated since proposal
to be about $20 million and is distributed among 37,500 CCT's. The EPA
believes this cost is reasonable.
Compared to a rule prohibiting the use of Cr+6-based water treatment
chemicals in CCT's, a rule based on HEDE's would be less effective and
would require retrofit of a large number of CCT's at greater expense.
Furthermore, there is no evidence that dissemination of Legionella
pneumophila would be reduced by HEDE's. Thus, EPA has concluded that a
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prohibition of use of Cr+6-based water treatment chemicals is appropriate
because substitutes are available and prohibition costs are reasonable.
2.3.8 Comment
One commenter (IV-D-26) strongly supports the use of TSCA to minimize
the health risks of Cr*6 emissions because (1) adequate substitutes for
chromate are available, (2) it is the most effective means of eliminating
human exposure, (3) it avoids cross-media transfer of risks, and (4) it
minimizes EPA's burden of enforcement. In addition, the commenter
believes that full enforcement of the rule is an extremely cost-effective
way of advancing environmental protection objectives and urges EPA to
devote adequate resources to ensure compliance with the rule.
Response. The EPA agrees with the commenter's assessment of the rule
and the need for adequate enforcement to ensure its effectiveness. The
enforcement burden of about 1,800 person-hours per year will involve
checking the shipment records at an estimated 200 water treatment chemical
distributors, spot-checking a portion of CCT facilities to determine
compliance with the rule, and processing export notifications. The TSCA
provides EPA with adequate enforcement authority, including the authority
to impose fines for noncompliance, and EPA plans to provide resources for
enforcement of the rule after it becomes effective.
2.3.9 Comment
One commenter (IV-D-24) believes that the use of chromates requires
regulation but prohibition is unwarranted. The commenter (IV-0-35) later
clarified this comment by indicating that regulation should be at the
point of use or disposal rather than at the point of shipment for use.
Response. This rule does regulate Cr+6-based water treatment
chemicals at the point of use by prohibiting its use in CCT's.
Distribution in commerce of Cr+ -based water treatment chemical for use in
CCT's also is prohibited because enforcement of the rule can more easily
be accomplished by inspecting the shipment records of 200 water treatment
chemical distributors than by inspecting 37,500 CCT's. These are the
least burdensome requirements to protect against the risk to human health
from Cr+6 emissions from CCT's.
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2.3.10 Comment
One commenter (IV-D-9) recommended that regulatory decisions on
chromium be directed toward specific compounds, not to Cr+6 1n general,
and that more studies on commercially Important compounds be made using
treatment methods (and solutions) that reproduce human exposure routes.
The proposed rule should be postponed until there 1s sufficient evidence
to support the need for a regulation on sodium dlchromate.
Response. The Administrator has determined that the use of
Cr+6-based water treatment chemicals in CCT's poses an unreasonable risk
to human health. Because of the potential adverse health effects
associated with Cr"1"6 exposure, EPA initiated a review to determine the
risks to public health from exposure to chromium in the ambient air. As
part of this review, a comprehensive HAD was prepared that summarizes the
scientific literature on health effects of chromium and emphasizes the
inhalation route of exposure. The HAD was reviewed at a public meeting of
the Environmental Health Committee of EPA's Science Advisory Board on
November 1, 1983. The Science Advisory Board concurred with the major
findings of the HAD including the finding that there is sufficient
evidence from the combined human and animal data to consider all Cr*6
compounds (Including sodium dichromate, the most commonly used chromium
compound for corrosion inhibition) to be carcinogenic, in humans.
Therefore, EPA believes that there is no compelling reason to postpone a
regulation to limit emissions of Cr"1"6 from CCT's.
2.3.11 Comment
One commenter (IV-0-11) indicated that the proposed rule does not
clearly describe how products for use in CCT's should be distinguished
from products for use in ICT's. To make the distinction, the commenter
believes that all products formulated with Cr+s should be distinctly
labeled as prohibited for use in CCT's.
Response. The proposed rule stated that persons who distribute in
commerce Cr+6-based water treatment chemicals shall affix a label or keep
an existing label affixed. The label has been revised slightly to clarify
that CCT's are open water recirculation devices. The label is required to
read as follows:
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Warning: This product contains hexavalent chromium. Inhalation of
hexavalent chromium air emissions increases the risk of lung
cancer. Federal law prohibits use of this substance in comfort
cooling towers, which are towers that are open water recirculation
devices and that are dedicated exclusively to, and are an integral
part of, heating, ventilation, and air conditioning or refrigeration
systems.
Since proposal, the definition of water treatment chemicals has been
revised and definitions have been included in the rule for several
additional terms. These new and revised definitions clarify that the
labeling requirement applies to shipments of Cr"l"6-based water treatment
chemicals for use in cooling systems, not just in cooling towers.
2.4 RECORDKEEPING AND REPORTING REQUIREMENTS
2.4.1 Comment
Nine commenters (IV-D-11, -13, -16, -18, -19, -20, -21, -22, and -23)
indicated that the requirement to retain records on all CCT customers and
all water treatment chemicals used in CCT's, as well as on ICT customers
using chromate water treatment, would create a significant burden on water
treatment chemical distributors. Two commenters (IV-D-19 and IV-D-22)
believe that requiring records on nonchromium products (especially from
distributors that sell no chromium products) will not help in enforcement
of the rule. One of these commenters (IV-D-22) also believes that EPA
enforcement personnel can do a better job if they are not burdened with
all the extraneous paperwork on nonchromate use. Another commenter
(IV-D^21) believes that regulation of all chemicals used in water
treatment would be a tremendous burden because of the extra paperwork; the
commenter questioned why shipping records must be provided for nonhealth
hazard chemicals.
Response. Since proposal, EPA has reevaluated the need for records
of shipments of nonchromate treatment chemicals for use in CCT's and has
decided not to require maintenance of these records. It was determined
that enforcement of the rule would be accomplished by other provisions and
that requiring recordkeeplng of nonchromate shipments would be unneces-
sary. In the final rule, recordkeeping of shipments of Cr+6-based water
treatment chemicals is required. The EPA also revised the definition of
water treatment chemicals and included definitions for several additional
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terms to clarify that the recordkeeping applies to shipments of Cr+6-based
water treatment chemicals for use in cooling systems, not just for use in
ICT's. The net result of these changes is that the cost burden to
industry for recordkeeping will be lower than projected at proposal. See
the response to Comment 2.5.8 for the revised estimate of the
recordkeeping burden.
The recordkeeping provisions described above are required so that
enforcement personnel may check records to determine compliance with the
rule by the water treatment chemical distributors. The recordkeeping also
will aid in determining sites where Cr"1" -based water treatment chemicals
are being used in cooling systems. This will enable EPA to target and
prioritize. Industrial cooling towers and closed cooling water systems in
which these chemicals are used likely to be colocated with CCT's.
Therefore, these will be locations at which inspection activities are
focused. Existing records kept by water treatment chemical distributors
are expected to meet the recordkeeping requirements of this rule with only
slight modifications.
2.4.2 Comment
One commenter (IV-D-11) represents a water treatment chemical
distributor that does not maintain telephone numbers, contact names, or
type of cooling tower in its billing records. Therefore, this information
is not available at the distributor headquarters. The commenter indicated
that to comply with the rule, the distributor would have to change its
billing system, which would be an unnecessary burden because the
information could be obtained, as needed, on a specific account under
review.
Response. As noted in the response to Comment 2.4.1, the requirement
that distributors maintain records of shipments of all water treatment
chemicals for use in CCT's has been deleted. The final rule requires only
that shipment records of Cr* -based water treatment chemicals for use in
cooling systems be maintained. Existing records kept by affected water
treatment chemical distributors can be modified slightly to include the
information required by the rule for shipments of Cr"1"6-based water
treatment chemicals. The requirements are the minimum necessary to ensure
effective compliance with the rule.
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2.4.3 Comment
One commenter (IV-D-18) questioned EPA's authority under TSCA to
require shipping records and records on chemicals that are not controlled
by TSCA. Three other comnenters (IV-D-19, -20, and -23) believe that EPA
does not have the authority to require such records. Two comnenters
(IV-D-18 and IV-D-23) noted that TSCA Section 6(a) provides EPA with the
authority to further regulate the use of a chemical determined to cause an
unreasonable risk to human health or the environment. The two commenters
also indicated that TSCA Section 8(a) provides EPA with the authority to
require ancillary recordkeeping for Section 6(a) chemicals. However, the
commenters believe that the proposed rule's recordkeeping requirements for
chemicals that have not been shown to cause unreasonable hazards to human
health or the environment are not covered by either TSCA section. Also,
one commenter (IV-D-23) indicated that TSCA Section 8(a) is rather
specific regarding the type of recordkeeping that can be required, and
shipping records are not one of the types of records listed.
Response. Since proposal, EPA has reevaluated the need for records
of shipments of nonchromate treatment chemicals for use in CCT's and has
decided not to require maintenance of these records.
2.4.4 Comment
Seven commenters (IV-D-13, -18, -19, -20, -21, -22, and -23) were
concerned that the recordkeeping requirements in the proposed rule would
place an unreasonable burden on the resources of small businesses. One
commenter (IV-0-13) indicated that many (if not most) water treatment
chemical distributors are small businesses without the computers or
manpower to comply with the proposed recordkeeping requirements.
Response. There may be water treatment chemical distributors that
are small businesses. However, EPA does not believe that the resources of
small businesses will be unduly burdened by compliance with the
recordkeeping requirements of the rule, especially since the final rule
requires that only records of Cr"l"6-based water treatment chemical for use
in cooling systems be maintained. Existing records kept by small water
treatment chemical distributors are expected to meet the recordkeeping
requirements of this rule with only slight modification. Storage capacity
(either computer or paper files) is not expected to increase. In
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addition, a distributor that does not need a computer now will not need to
purchase one to comply with the recordkeeping requirements of the rule.
The total cost to the water treatment chemical industry of labeling,
recordkeeping, and reporting requirements 1s estimated to be about
$87,000/yr. This cost 1s less than 1 percent of gross water treatment
chemical Industry sales of approximately $90 mHHon/yr. The average cost
burden that individual distributors of Cr+6-based water treatment
chemicals would incur as a result of the labeling, recordkeeping,
reporting (includes export notification) requirements is estimated to be
$435/yr over a 3-year period. Therefore, the cost of recordkeeping
requirements of the rule 1s not expected to cause any economic hardship on
small businesses.
2.4.5 Comment
One commenter (IV-0-18) indicated that maintaining all CCT records
for 2 years will require time and archive space that many water treatment
chemical distributors cannot afford. Another commenter (IV-0-21) believes
that additional people would have to be hired to handle the extra
paperwork.
Response. As noted in the response to Comment 2.4.1, the requirement
for retention of records on all water treatment chemicals for use in CCT's
has been deleted, and only records of Cr*6-based water treatment chemicals
are required to be maintained. The EPA believes that the majority of
distributors already keep most, if not all, of the required information
and that only slight modifications will be necessary to meet the
requirements of the rule.
2.4.6 Comment
One commenter (IV-0-16) believes that the requirement to maintain
records of a contact name of any CCT user to whom water treatment
chemicals are shipped is unfair because water treatment chemical
distributors would have to keep track of CCT owner/operator personnel
changes.
Response. Under the final rule, recordkeeping requirements only
apply to shipments of Cr+6-based water treatment chemicals for use in
cooling systems. Water treatment chemical distributors will need to
retain contact names of ICT users and those CCT users with closed cooling
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water systems that are receiving Cr"1"6 chemicals. The EPA believes that
most companies that order water treatment chemicals identify a specific
person responsible for placing that order or to whom the order should be
shipped. Thus, distributors will not have to "keep track of" personnel
changes but merely will need to record the name associated with an
individual order.
2.4.7 Comment
One commenter (IV-D-23) indicated that because water treatment
chemical distributors are required to submit annual reports under FIFRA on
all biodde chemicals and reports every 5 years under TSCA on all
chemicals, 1t seems ridiculous to have to maintain all shipping records
for 2 years.
Response. The annual reports required by FIFRA only apply to the
biocides used in cooling towers, and biocides are not included as part of
the corrosion inhibitor formulation. Consequently, these reports will not
help in enforcement of the rule. The commenter's reference to a TSCA
report every 5 years .is unclear because there is no such requirement in
TSCA. In any case, as noted earlier, the recordkeeping requirements have
been revised since proposal, and maintenance of records of shipments of
nonchromate water treatment chemicals is no longer required. The
recordkeeping requirements in the final rule have been limited to those
that are necessary to ensure effective compliance with the rule.
2.4.8 Comment
Seven commenters (IV-0-11, -13, -16, -19, -21, -22, and -23) believe
that it would be sufficient and more appropriate to maintain records only
on customers still receiving Cr+6-based water treatment chemicals; records
indicating that these chemicals were shipped only for use in ICT's would
show compliance with the prohibition of use in CCT's. As an alternative,
three commenters (IV-D-11, -13, and -16) believe that information on
CCT's, if necessary, should be supplied by the CCT owners/operators or by
the CCT manufacturers, not by the water treatment chemical distributors.
Response. As described in the response to Comment 2.4.1, EPA has
reevaluated the recordkeeping requirements and agrees with the commenters
that records of Cr*6-based water treatment chemicals are adequate to
ensure compliance with the rule. Therefore, only records of shipments of
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Cr"1" -based water treatment chemicals are required in the final rule. The
EPA also has clarified that the recordkeeping requirement applies to
shipments of Cr"*"6-based water treatment chemicals for use in cooling
systems, not just for use in ICT's.
The EPA disagrees that CCT owners, operators, or manufacturers should
supply the records necessary to ensure compliance. For purposes of
determining compliance with this rule's requirements, EPA has determined
that the most effective approach is to require recordkeeping by persons
who distribute Cr+6-based water treatment chemicals in commerce. The EPA
has also determined that recordkeeping by the water treatment distributors
significantly reduces the overall recordkeeping, reporting, and
enforcement burden of the rule because the number of distributors is much
smaller than the number of CCT owners, operators, and manufacturers.
2.4.9 Comment
One commenter (IV-D-11) suggested that persons distributing
Cr"1" -based water treatment chemicals should be required to provide each
publicly owned treatment works (POTW) with records that identify cooling
tower owners/operators in the POTW district that receive shipments of the
chemicals.
Response. The purpose of the recordkeeping requirements is to
provide information necessary for EPA to determine compliance with the
prohibition of use of Cr+ -based water treatment chemicals and
distribution in commerce of the chemicals for use in CCT's. The
commenter's suggestion would impose an additional paperwork burden on
water treatment chemical distributors without contributing to the
effective enforcement of the rule. Therefore, EPA does not believe that
the suggested requirement is warranted, and it is not included in the
final rule.
2.4.10 Comment
One commenter (IV-0-16) requested that the final rule include a
statement indicating that records will be kept confidential. The
commenter wants to ensure that a water treatment chemical distributor will
not be able to obtain copies of a competing distributor's customer list
under the Freedom of Information Act (FOIA).
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Response. Any person who submits information to EPA can request that
the information be treated as confidential business information (CBI)
under TSCA. In any event, the only information that is required to be
reported to EPA under this rule is the name, address, telephone number,
and contact name for the headquarters and shipment offices and a statement
related to whether the distributor distributes in commerce any Cr+6-based
water treatment chemicals. Records of Cr+6-based water treatment
chemicals are to be retained at the distributor headquarters and would not
be subject to FOIA requests. These records would only be available to
authorized EPA enforcement personnel.
2.4.11 Comment
Six commenters (IV-D-18, -19, -20, -21, -22, -23) were opposed to the
reporting requirements of the proposed rule, particularly for nonchromate
water treatments. Two commenters (IV-D-18 and IV-D-23) stated that
because of the numerous reporting requirements already in place, including
those under the Superfund Amendments and Reauthorization Act (SARA), OSHA,
TSCA, FIFRA, and State and local laws, the drain on resources for small
businesses is large. One commenter (IV-D-18) believes that completing the
initial report required by the proposed rule, in addition to the proposed
recordkeeping requirements, will require time and archive space these
small companies cannot afford.
Response. The EPA has reevaluated the reporting requirements and has
decided not to require reports by distributors that provide only
nonchromate water treatment chemicals. It was determined that these
reports would be unnecessary because enforcement of the rule would be
accomplished by other provisions. However, in the final rule, reporting
by distributors of Cr+6-based water treatment chemicals is required. The
required reporting is minimal and consists of identification of the
distributor name, address, telephone number, and name of contact for both
the headquarters and shipment office locations. The reporting require-
ments also have been clarified to indicate that they apply to distributors
of Cr -based water treatment chemicals for use in cooling systems. At
proposal, reporting was required by distributors of water treatment
chemicals for use in CCT's and by distributors of Cr+6-based water treat-
ment chemicals for use in ICT's. The clarification should not increase
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the reporting burden because most distributors provide chemicals for use
in both cooling towers and closed cooling water systems. As stated in the
response to Comment 2.5.8, the cost of the reporting requirements averaged
over the first 3 years of the rule for distributors of Cr^-based water
treatment chemicals 1s estimated to be about $30 per company per year.
Therefore, EPA believes that the reporting requirements of the final rule
do not pose an undue burden on water treatment chemical distributors.
2.4.12 Comment
One commenter (IV-D-13) suggested that the reporting responsibility
for Cr"l"6-based water treatment chemicals should lie directly with the
users/consumers. The commenter believes that the authority to handle this
may already be in place and operational under SARA, Title III Section 302
et al.
Response. As discussed in the response to Comment 2.4.8, EPA has
determined that the large number of CCT owners and operators would
preclude the effective imposition of recordkeeping requirements on the
user population, particularly when the objectives of the rule can be met
with far less overall burden by the much smaller groups of water treatment
chemical distributors. Similar reasoning applies to the imposition of
reporting requirements. Furthermore, the reporting requirements under
SARA apply only to releases of "reportable quantities" of hazardous
substances in a 24-hour period. The reportable quantity of sodium
dichromate is 454 kilograms (1,000 pounds), which is significantly more
than would be emitted from any cooling tower in a 24-hour period.
Consequently, the responsibility for reporting will continue to remain
with the water treatment chemical distributors.
2.4.13 Comment
One commenter (IV-0-33) stated that the reporting requirements
require the creation of two separate lists; one based on invoicing and the
other based on end use locations. The commenter noted that in cases where
materials are purchased by a company and shipped to a central location for
use at separate facilities, the distributor may not know the actual end
use location. The commenter recommended that this reporting be minimized
to avoid adverse costs to smaller water treatment distributors.
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Response. The commenter is correct that under the scenario
described, the water treatment chemical distributor would be required to
collect and maintain information that may not be currently maintained.
However, effective enforcement of this regulation depends on the
identification of end use locations of Cr*"6-based water treatment
chemicals. The cost that would be faced by the distributor would be to
redesign and print the order form to incorporate end use location. The
EPA believes that this cost is reasonable and it has been incorporated
into the revised estimate of industry burden which is discussed in the
response to Comment 2.5.8.
2.5 ECONOMIC AND COST IMPACT
2.5.1 Comment
Two commenters (IV-D-27 and IV-F-1 [Sefton]) believe that EPA has
underestimated the cost impact of the proposed rule. Based on conversa-
tions with water treatment chemical distributors, one commenter (IV-D-27)
believes that the cost of technical service provided by the distributors
will Increase significantly with nonchromates, whereas the proposal BID
Indicates that the cost is not expected to increase significantly. The
monitoring and control equipment necessary to use nonchromates are esti-
mated by the commenter to cost between $5,000 and $10,000 per CCT
system. Another commenter (IV-F-1 [Sefton]) sells a basic control system
for over $2,500 (not including installation costs) that includes automated
feed, bleed-off, and pH control equipment. If separate acid feed or
mixing equipment is required, the cost would be even higher. Consequently,
the commenter believes that EPA's estimate of $500 for this type of
equipment is extremely low. The commenter also believes EPA's estimate of
15-year life expectancy for this equipment is optimistic because many
components, such as pH probes, were found to have life spans as short as
1 year or less. To illustrate annual nonchromate treatment program costs,
the commenter selected as examples four typical CCT's (150 to 350 tons)
using different nonchromate treatment programs for which the annual costs
were $2,160 to $4,590. These costs include the cost of the corrosion
inhibitor and technical service as well as other expenses such as
additional biocides for phosphate programs; however, annualized equipment
costs are not included. In addition to the control equipment and chemical
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treatment costs, Conroenter IV-0-27 believes that additional staff would be
needed to monitor the equipment, Instrumentation, and CCT's.
Response. To respond to this comment, EPA obtained additional
Information about automatic control equipment and water treatment program
costs from water treatment distributors and other contacts. The
additional Information provided shows that costs for both control
equipment and nonchromate treatment program chemicals and technical
service were underestimated in the proposal BID, but not by as much as the
commenters have suggested. The revised cost estimates are summarized
below and are discussed in more detail in docket item IV-B-1.
In the proposal BID, it was reported that the only necessary
automatic control equipment was a blowdown controller, and the controller
life was assumed to be 15 years. New information from six water treatment
chemical distributors shows that a chemical feed pump and a water meter
also are needed and that equipment life expectancy should be 10 years.
The information also indicates that acid is added in about 25 percent of
the CCT's to reduce pH and alkalinity levels. For these CCT's, a pH
controller and an acid feed pump would be needed in addition to the other
equipment described above. Finally, it was assumed that about 3 percent
of all CCT's are in high-rise buildings that would need high-pressure feed
pumps.
The revised capital costs were based on information obtained from six
water treatment chemical distributors, one automatic control equipment
manufacturer, and one CCT user. All of the estimated capital costs are
purchase costs. Installation costs have not been included because it was
assumed that installation would be performed by the building or facility
maintenance personnel as part of their regular duties. The revised costs
that would be incurred by a typical CCT for a blowdown controller,
standard corrosion inhibitor feed pump, and water meter are about
$1,100. For the 25 percent of CCT's that also add acid to reduce pH and
alkalinity levels, a pH controller and an acid feed pump would cost an
additional $1,150. For the 3 percent of the CCT's that would require a
high-pressure pump, the capital cost would increase by $450. Based on
these estimates, the average capital cost per CCT has been revised to
$1,400. In addition to the initial capital costs, the new information
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indicates that replacement of conductivity probes is necessary every
3 years at a cost of $100, and pH probes must be replaced every 2 years at
a cost of $150. Based on these capital and replacement costs, the
annuallzed automatic control equipment cost 1s about $300 per CCT.
The chemical treatment program costs reported 1n the proposal BID
were underestimated because they were average costs for both Id's and
CCT's and because they did not Include bioclde costs. For nonchromate
programs, the revised chemical treatment program costs were based on
estimates provided by seven water treatment chemical distributors and two
CCT users. For nonchromate programs, the revised chemical treatment cost
1s $300/m1ll1on pounds (M Ib) of blowdown, which is 150 percent higher
than the estimate at proposal. The revised chemical treatment cost for
chromate programs is $215/M Ib of blowdown, which is 260 percent higher
than the proposal estimate. These estimates include the cost for biocides
as well as for the cost for the corrosion inhibitor formulation.
The total annual cost to switch CCT's from chromate to nonchromate
treatment programs is the sum of the annual cost difference between
nonchromate and chromate treatment programs, the annualized capital cost
for control equipment, and the annuallzed cost for replacement
equipment. The total annual nationwide cost is estimated to be
$20 million, which is more than two times higher than the $9.4 million in
the proposal BID. This new estimate is based on the worst-case assumption
that all 37,500 CCT's switching from chromate to nonchromate treatment
programs would need to install automatic controls. Even under this worst-
case scenario, EPA believes the estimated costs are reasonable as is the
revised cost-effectiveness value. Cost effectiveness was calculated using
the total annual nationwide cost and a revised estimate of the annual
incidence based on a best estimate of the emissions (see docket
item IV-B-1). The calculated cost effectiveness of eliminating Cr+6-based
treatment programs is $1 million per cancer case avoided.
The economic impact of the rule has been revised based on the new
costs. As indicated in the proposal BID, if it is assumed that the costs
will be passed on in the form of rental rate increases, the average impact
on rental rates for the smallest size towers is estimated to be less than
$0.45/square meter (m2) ($0.04/square foot [ft2]). This cost would
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represent a rent Increase of about 0.3 percent. The impact on rental
rates decreases as CCT (and building) size increases.
The costs discussed above do not Include costs for additional staff
to monitor the equipment, Instrumentation, and CCT's as suggested by the
commenter. The level of effort to monitor, control, and maintain a CCT
system using a nonchromate treatment program is similar to that for a CCT
using a typical chromate program. Typical activities include sampling the
cooling water on a weekly or daily basis (30 minutes); analyzing the
samples for the inhibitor or tracer concentration (10 to 20 minutes);
visual inspection of the system daily; adjusting the automatic controls,
as necessary; inspecting and cleaning the chemical feed system, cooling
water pump, and conductivity sensor once a month (about 1 hour); and
periodically adding biodde (and acid, 1f not added automatically). These
activities require a level of effort of up to about 2 hours per day
(h/d). Most building support staffs consist of at least two persons
between whom the work can be divided. The impact on most building support
staffs may be significantly less than 2 h/d because weekly checks of the
water are sufficient for many automatically controlled nonchromate
programs; simple analyses are available for molybdate, zinc, and
phosphate; and operators of CCT's on typical chromate programs already
perform some of these tasks.
2.5.2 Comment
One commenter (IV-F-1 [Sefton]) believes that the economic impact of
the proposed rule on individual CCT's using poor quality makeup water that
contains high chloride, hardness, and alkalinity levels would be enormous
(specifically 1n the Florida area) and estimates that the total costs
could exceed $1 billion for Florida alone. The commenter indicates that
both the replacement frequency of highly corrodible components of the CCT
system and the replacement of these components with more expensive
corrosion-resistant components must be considered. The commenter
described specific repairs and improvements that could be required and
provided the costs for some of them.
The commenter also believes that higher operating costs are incurred
by CCT's in Florida using poor quality water supplies. In many cases,
more frequent cleaning of the heat transfer equipment would be necessary
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to remove scale, which is produced by many of these water supplies at the
effective pH levels of the inhibitors. Cleaning may be accomplished on-
line with expensive and unpredictable chelating agents. Alternatively,
the system could be shut down and cleaned with acid, which can cost $500
or more depending on the size of the chiller. Scale impairs the heat
transfer process and, thus, also results in higher energy consumption and
cost to maintain the design cooling requirement. Water costs also would
increase for these CCT's. To illustrate how water costs could increase,
the commenter presented the following example. If the cycles of
concentration in the CCT are kept low because corrosion inhibitors that
are less effective than chromate are used, water usage increases. At five
cycles of concentration (typical for chromate programs), bleed off is
about 0.7 gallons of water per minute (gal/min) per 100 tons of air
conditioning. At two cycles, the bleed-off rate would be about
2.7 gal/min per 100 tons of air conditioning. For a 1,000-ton CCT
operating at full capacity, the increase in water usage would be an
additional 20 gal/min or over 28,000 gal/d. The commenter indicated that
some water in Florida now costs over $5/1,000 gal, but even at
$3/1,000 gal, this increased water usage would result in increased
operating costs of over $2,500 per month.
Response. As indicated in the response to Comment 2.1.7, information
obtained by EPA from water treatment chemical distributors and other
contacts show that nonchromate programs are available that effectively
control corrosion in CCT's using makeup water containing high chloride,
hardness, and alkalinity levels. Consequently, EPA disagrees that more
frequent replacement of system components would be required for CCT's
using nonchromate chemicals with poor quality makeup water and has not
considered such costs in developing the final rule. Because these
programs also have been shown to control scale in high chloride/high
hardness water through the addition of acid and dispersants, the
commenter's claim that energy use would increase also is unsupported.
However, the additional information obtained by EPA indicates that the
commenter is correct in stating that increased water usage would occur for
these CCT's. To determine the impact of the increased water costs and to
incorporate revisions to other costs resulting from the new information,
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EPA conducted a new cost analysis for CCT's using water with high
chloride, hardness, and alkalinity levels such as those in Florida. The
total annual cost for a hypothetical analysis of nonchromate substitution
for all Florida CCT's was estimated based on the additional cost of
chemicals, water, and automatic control equipment. The annual incidence
also was revised based on the typical chromate concentration provided by
the commenter and on the best estimate emission factor developed by EPA
since proposal. The following discussion summarizes the results of this
analysis, and docket item IV-B-2 further describes how the costs were
estimated.
Information on the chemical cost of treating cooling water with high
chloride, hardness, and alkalinity levels was solicited from several water
treatment chemical distributors. Only two distributors provided chemical
cost information, and this information was used to calculate the chemical
cost difference between nonchromate and chromate treatment programs in
Florida. These costs include the cost of the corrosion inhibitor, acid,
dispersants, and bioddes. An 89 percent utilization rate was assumed for
the Florida CCT's, which is higher than the nationwide average rate of
46 percent. Based on Information received from two water treatment
chemical distributors, the Florida CCT's were assumed to operate at
3.8 cycles of concentration as opposed to 5 cycles of concentration
assumed in the proposal BID. Therefore, the makeup water rate in Florida
towers using the poor quality makeup water is about 9 percent higher than
average. The water cost for Florida was assumed to be $3/1,000 gallons,
also higher than the nationwide average. Automatic control equipment
capital costs for Florida were assumed to be no different from the costs
for an average CCT (see the response to Comment 2.5.1). Finally, for the
purpose of this analysis, it was assumed that all chromate-using CCT's in
Florida use water with high chloride, hardness, and alkalinity levels,
thus overstating the cost impact.
Based on these assumptions, the total annual cost of the hypothetical
analysis for approximately 1,700 chromate-using CCT's in Florida to switch
to nonchromate treatment programs is estimated to be about $6.6 million,
much lower than the $1 billion estimated by the commenter. The hypothe-
tical annual incidence for this analysis was estimated to be about
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3 cases/yr. This annual incidence 1s based on a chromate concentration of
25 ppm rather than 10 pp» as reported 1. the proposal BID. The higher
concentration was used because the counter Indicated that the typical
drartt concentration In towers using the poor quality water 1s greater
than 20 PPn. Even under this worst-case scenario. EPA believes the
estimated costs are reasonable as 1. the revised cost-effectiveness value
of $2 mm ion per cancer case avoided.
2.5.3 Comment . .
Onelo^enter (IV-F-1 [Sefton]) believes that the proposed rule would
have a significant economic impact on small businesses using CCT's with
makeup water with high chloride, hardness, and alkalinity levels. To
illustrate this impact, the commenter estimates that a 15-story
condominium could incur high costs to repair corrosion damage or to
upgrade the equipment before failure. The commenter also noted that
annual operating costs for such a building could increase by $50,000 due
to increased chemical costs, increased water usa^e, and higher energy
costs (in high-scaling situations).
Response. As discussed in the response to Comment 2.5.2, EPA does
not believe that CCT's using water with high chloride, hardness, and
alkalinity levels will need to replace or repair equipment due to
corrosion any more frequently when using nonchromate programs than when
using chromate programs. However, EPA's revised cost analysis for such
CCT's did show that annualized costs would be greater for them than for
CCT's using good quality water. The revised total annual costs for
switching from chromate to nonchromate programs for CCT's in these poor
water quality areas (such as Florida) ranged from about $600 per year for
the smallest model tower (27 tons) to $18,400 per year for the largest
model tower (1,520 tons). These costs are higher than those for average
CCT's, but the average impact on rental rates for the smallest building is
estimated to be less than 1 percent. These costs and the impact on rental
rates are considered reasonable.
2.5.4 Comment
One commenter (IV-D-27) believes that the cost to repipe buildings
because of total system failure should be addressed because some buildings
with heavily corroded CCT systems have been faced with this cost soon
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after they switched to nonchromate treatment programs. For a high-rise
building with an extensive piping network, this cost would overwhelm the
other costs of switching to nonchromates. The commenter cited corrosion
rates of 7 to 10 mils/yr under chromate programs and 7 to 30 mils/yr under
nonchromate programs for systems using soft, naturally corrosive New York
City municipal water.
Response. As indicated in the response to Comment 2.1.3, the
majority of CCT systems using chromate treatment programs are not heavily
corroded and can be easily switched to nonchromates. However, two options
exist for dealing with heavily corroded systems that are switched to
nonchromates. These options are (1) switching directly to nonchromate
treatment programs without cleaning (noncleaning option) and (2) cleaning
before or concurrent with the switch to nonchromate treatment programs
(cleaning option). The EPA evaluated the total annual cost, annual
incidence, and cost effectiveness of the rule for these options. The
analysis was performed for all six model towers and is discussed in detail
in docket item IV-B-3. However, only the results of the analysis for the
largest model tower are summarized below because this model tower
represents the CCT's used in high-rise buildings as described by the
commenter.
The cost of both options is a function of the pipe life. The life of
new pipe was estimated to be 40 years based on corrosion rates of
2 mils/yr, the assumption that most of the system consists of 2-inch
diameter pipe which has a wall thickness of 154 mils, and the assumption
that the pipe would need to be replaced when less than half of the
original wall thickness remains. For the noncleaning option, the average
pipe life was estimated to be about 4 years under chromate programs and
about 1 year under nonchromate programs. This estimate is based on the
above assumptions and the highest corrosion rates observed by the
commenter under both programs. The highest corrosion rates were used
because this pairing results in the earliest need for pipe replacement
after switching to nonchromates. The average pipe life for the cleaning
option was estimated to be 19 years, or 15 years longer than for the
existing chromate program. This estimate is based on the above assump-
tions and the information presented in the response to Comment 2.1.3.
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This information shows that even heavily corroded systems can be cleaned
adequately and that acceptable corrosion rates of 2 mils/yr can be
achieved with nonchromate treatment programs 1n the cleaned systems.
The total annual cost of the noncleanlng option 1s based on the
annuallzed pipe replacement cost for the years of life lost by switching
to nonchromate treatment programs, the additional annual chemical cost for
nonchromate programs, and the annualized automatic control equipment
cost Based on information from one water treatment chemical distributor,
the pipe replacement cost was estimated to be $215,000. As indicated
above, this cost would be incurred 3 years earlier under the none!earnng
option than under the existing chromate program. Using the pipe
replacement cost, the 3 years of life lost by switching to nonchromates,
an assumed building life of 40 years, and an interest rate of 10 percent;
the annualized pipe replacement cost of the noncleaning option was
estimated to be $5,100/yr.
The annual chemical cost difference between chromate and nonchromate
programs was estimated to be about $2,900/yr based on cost data from two
water treatment chemical distributors for soft water applications. The
cost data provided were scaled to the New York City utilization rate of
33 percent. The average annualized automatic control equipment cost is
about $300/yr. This cost is the same for all towers, as described in the
response to comment 2.5.1. Based on these costs, the total annual cost of
the noncleaning option is estimated to be about $8,200/yr for the largest
size model tower.
The total annual cost of the cleaning option is based on (1) the
annualized difference between the initial cost for cleaning and the
present value of the cost of continuing to use chromate in a corroded
system and (2) the same increased chemical and automatic control equipment
costs as for the noncleaning option. The cleaning cost was estimated to
be $37,500 based on information from a cleaning company. As indicated
above, the estimated pipe replacement cost of $215,000 would be incurred
15 years earlier under the existing chromate program than under the
cleaning option. The present value of the annualized pipe replacement
costs for these 15 years is $110,000. This cost indicates that cleaning
results in a present value cost savings of about $73,000, or an annual
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cost savings of about $7,800/yr, over the existing chromate program. Even
when the additional chemical and automatic control equipment costs are
included, the cleaning option results in an annual cost savings of about
$4,700/yr.
For heavily corroded systems, the annual incidence is estimated to be
three times higher than average. This annual incidence is based on a new,
best estimate of the Cr"1"6 emissions and a tower utilization rate of
33 percent. The annual incidence also is based on a chromate
concentration of 40 ppm which, according to the commenter and two water
treatment chemical distributors, is typical for soft water applications
such as those in New York City.
The total annual cost of $8,200/yr for the noncleaning option, the
option with the highest cost, was used in analyzing the total annual cost
of switching heavily corroded systems to nonchromate treatment programs.
Based on this cost and the revised annual incidence, the best estimate of
the cost effectiveness is about $1 million per cancer case avoided. The
EPA believes these costs are reasonable.
In addition to the cost analysis for heavily corroded systems, EPA
also evaluated the cost for clean CCT systems using soft water because the
commenter claimed that corrosion rates are worse in soft water than in
scale-forming water (see Comment 2.1.6). This analysis is summarized
below and is presented in detail in docket item IV-B-4. As indicated in
the response to Comment 2.1.6, information obtained by EPA from water
treatment distributors shows that acceptable corrosion rates can be
achieved with nonchromate treatment programs in CCT's using soft water.
Therefore, the cost of the rule for CCT's using soft water is based on the
same annual chemical and automatic control equipment cost information
described above except that the provided chemical cost was scaled to the
nationwide average utilization rate of 46 percent. It also was assumed
that the distribution of the six model towers using soft water is the same
as the nationwide distribution of the model towers. Based on these
assumptions and conditions, the total annual cost of the rule ranges from
about $300/yr for the smallest model tower to about $3,600 for the largest
model tower. As with the analysis for heavily corroded systems, the
annual incidence was revised using a typical chromate concentration of
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<0 ppn, for soft «ater applications. The cost effectiveness based on these
costs and revised annual Incidence values 1s about $500,000 per cancer
case avoided. The EPA believes these costs ar« reasontble.
2.5.5 Cownent ^ . fcl%j%
Onelo^enter (IV-F-1 [Sefton]) believes that the estimates 1n the
proposal BID for the distribution of the total CCT population on a per
capita basis underestimates both the number of cooling towers in warm
regions of the U.S. and the economic impacts for those areas. For
example, the commenter estimates that 6,250 CCT's in Florida use chromate
and that the economic impacts of the proposed rule on these towers could
exceed $1 billion. This estimate includes the cost to replace corroded
pipes.
Response. The total CCT population was distributed on a per capita
basis because this was and still is the best method available. Buildings
may not need as much cooling in cool areas of the U.S., but they still use
cooling towers. In cool areas, the CCT's operate at lower utilization
rates or they may be smaller than those in warm regions. Consequently,
EPA believes that the distribution of CCT's on a per capita basis is
reasonable.
As discussed in the response to comment 2.5.1, the nationwide economic
impact of the rule was revised from $9.4 million to $20 million. This
analysis averages the costs for CCT's nationwide. Therefore, it over-
estimates the cost for CCT's with utilization rates below the average, for
CCT's that operate with higher than average cycles of concentration, and
for CCT's that already have automatic control equipment. On the other
hand, the analysis underestimates the cost for CCT's using makeup water
that is highly-scale forming and for CCT's with utilization rates above
the average. The commenter is correct that Florida is one area where the
cost per CCT is higher than average. However, as discussed in the
response to comment 2.5.2, EPA conducted a hypothetical cost analysis for
Florida and found the total annual cost to be less than $6.6 million even
if all Florida CCT's were assumed to use high chloride makeup water,
considerably less than the $1 billion estimated by the commenter.
Consequently, EPA believes that the cost and economic impact of the final
rule is estimated adequately by distribution of the CCT's on a per capita
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basis. Furthermore, underestimation of the number of towers using
chromate 1n a region also would result in underestimation of the emissions
and risk. Because the cost and risk are both directly proportional to the
number of towers, the cost effectiveness would be the same regardless of
the number of towers.
2.5.6 Comment
One commenter (IV-F-1 [Murphy]) indicated that good corrosion
protection was necessary to keep cooling towers, condenser tube bundles,
tube sheets, and piping from corroding at rates that require repair or
replacement in only a short time. Damage to condenser heads and tube
sheets could require sandblasting and epoxy coating. The commenter
provided estimated costs and downtime that would be typical to repair
corrosion damage in a 500-ton system.
Response. The EPA agrees that good corrosion protection is necessary
to minimize the need for repair or replacement of CCT system components.
As discussed in the responses to Comments 2.1.3, 2.1.6, and 2.1.7, the
effectiveness of many nonchromate programs has been demonstrated even in
CCT's using poor quality makeup water. Consequently, the replacement
costs and downtime cited by the commenter would not be incurred by CCT's
that properly implement these nonchromate programs.
2.5.7 Comment
One commenter (IV-D-29) stated that EPA has not assessed the
potential consequences of conversion to nonchromates on older CCT
systems. The commenter believes that conversion to substitute chemicals
will lead to pinhole leakage in the system at least until the replacement
becomes stabilized. The commenter estimated that the overhead costs and
lost salaries would exceed $1 million per day if his facility had to be
shut down because of system failure. Another potential cost could be the
loss of critical data within computer systems.
Response. The EPA has assessed the potential for corrosion during
conversion of older CCT's to nonchromate treatment programs and concluded
that system failure or unplanned shutdown will not occur when the conver-
sion is properly conducted. Shutdown will not be necessary if the system
is clean before the switch, as the water treatment distributors indicated
is the case with most CCT's using chromates. Typical procedures that the
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water treatment companies follow .hen converting a system are presented in
the response to Consent 2.1.3. Because these procedures are well under-
stood by water treatment che»1cal distributors and cleaning contractors
CCT owner/operator should not Incur overhead costs or the loss of critical
data when switching to a nonchronate treatment program.
(IV-0-16) concluded that the estimated labeling,
recordkeeping, and reporting cost of $169,900 per year would be the
average cost of compliance for each of 400 water treatment chemical
distributors because the alternative of $425/year seems very low. This
would lead to the removal from the economy of about $68 million/year (or
$204 million over 3 years) that the commenter believes would be better
used by Investing 1n expansion.
Response. The commenter' s conclusion about the labeling,
recordkeeping, and reporting cost to Industry 1s Incorrect. For the
proposed rule, the estimated cost averaged over the first 3 years of the
rule was $425 per company and $169,900 for the Industry. These costs were
considered reasonable because most of the required records are kept by the
water treatment chemical distributors, and any additional Information
could be easily obtained and recorded after an initial modification is
made to the existing recordkeeping format. However, the labeling,
recordkeeping, and reporting burden has been reevaluated since proposal.
The requirement that records be maintained of nonchromate shipments to
CCT's has been deleted as described in the response to Comment 2.4.1, and
the reporting requirement has been revised as described in the response to
Comment 2.4.11 to exempt distributors that provide only nonchromate water
treatment chemicals. In addition, the cost impact of the export
notification requirements has been estimated. The labeling,
recordkeeping, and reporting requirements have also been revised as
described in the responses to Comments 2.3.11, 2.4.1, and 2.4.11 to
clarify that they apply to distributors that ship water treatment
chemicals for use in cooling systems; not just for use in cooling
towers These clarifications should not change the cost impact because
most distributors providing Cr+s-based water treatment chemicals for
closed cooling water systems also provide the chemicals for ICT's.
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At proposal, it was estimated that there are a total of about
400 water treatment chemical distributors. Since proposal, it was assumed
that about 200 of the distributors provide both Cr+6-based and nonchromate
water treatment chemicals, and the other 200 distributors provide only
nonchromate chemicals.
The 200 distributors providing Cr"*"6-based water treatment chemicals
would be affected by all of the labeling, recordkeeplng, and reporting
requirements. For these 200 distributors, the revised cost averaged over
the first 3 years of the rule is estimated to be $435 per distributor per
year. This cost comprises $30 for reporting, $225 for recordkeeping, and
$180 for labeling. In addition, the cost impact of the export
notification requirements accounts for a very small part of the total
annual cost. It was assumed that 10 of these 200 distributors also export
Cr+ -based water treatment chemicals to 1 country. For these
10 distributors, the estimated cost impact of the export notification
requirements averaged over the first 3 years of the rule is $50 per
distributor per year. The rule would have no cost impact on the
200 distributors selling only nonchromate chemicals because they would not
be affected by the labeling, recordkeeping, and reporting requirements.
The estimated annual cost for the water treatment chemical industry over
the first 3 years of the rule is about $87,000.
Producers of sodium dichromate and manufacturers of Cr+s chemicals
other than water treatment chemicals are also affected by the export
notification requirements. It is assumed that 2 producers of sodium
dichromate each export to 20 countries and that 20 chemical manufacturers
of Cr+6 chemicals each export to 1 country. For the producers, the
estimated cost averaged over the first 3 years of the rule is about
$1,000 per company per year. The cost impact for the chemical
manufacturers averaged over the first 3 years of the rule is $50 per
company per year.
2.6 SELECTION OF THE SOURCE CATEGORY
2.6.1 Comment
Eight commenters (IV-0-15, -17, -18, -19, -21, -22, -23, and -26)
believe that EPA should regulate Cr+S chemicals in CCT's, and five of the
commenters (IV-0-15, -18, -21, -23, and -26) support the proposed rule
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because they believe that Cr"1"6 is a health hazard that should be removed
from the environment. One commenter (IV-0-15) believes that Cr+ also
should be banned from use 1n boilers and closed hot and chilled water
cooling systems. This commenter also supports the proposed rule because
chromate is detrimental to pump seals and valve packings, stains floors
and ceilings, and 1s nonblodegradable. Another commenter (IV-D-17)
supports the proposed rule because users will not change to nonchromates
unless forced to do so.
Response. The proposed rule was based on EPA's determination that
the use of Cr"h6-based water treatment chemicals in CCT's presents an
unreasonable risk to human health and that TSCA is the most effective
means to control this risk. The final rule will effectively eliminate the
use of Cr"*"6-based water treatment chemicals in CCT's. The recordkeeping
and reporting provisions, by identifying both users and distributors of
Cr+6-based water treatment chemicals, will allow EPA to identify potential
violations by CCT operators and water treatment chemical distributors.
The labeling requirements will ensure that distributors and users are
aware of the hazard associated with Cr+6-based water treatment chemicals
and informed of the restrictions on their use.
However, EPA disagrees with the commenter that Cr+6-based water
treatment chemicals should be banned from boilers and other closed systems
under this rule. The EPA has determined that the primary exposure pathway
of concern is by inhalation of air emissions. Because airborne Cr+6
emissions are not expected from boilers, closed cooling water systems, and
closed chilled water loops, EPA has no current plans to prohibit use of
Cr"1"6 in these systems.
To clarify that the prohibitions on distribution and use do not
include closed systems (or ICT's), several changes have been made to the
rule. First, the following statement has been added to § 749.68(e) of the
rule:
Distribution in commerce of hexavalent chromium-based water treatment
chemicals for use in, and commercial use of hexavalent chromium-based
water treatment chemicals in, industrial cooling towers and in closed
cooling water systems are not prohibited.
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Second, several changes have been made to the definitions in § 749.68(d)
of the rule. A new term, "cooling system," has been defined as any
cooling tower or closed cooling water system. "Closed cooling water
system" also is a new term that has been defined as any configuration of
equipment in which heat 1s transferred by circulating water that 1s
contained within the equipment and not discharged to the air. One type of
closed cooling water system is a chilled water loop that transfers heat
from air handling units or refrigeration equipment to a refrigeration
machine or chiller. Finally, the definition of the existing term "water
treatment chemicals" has been revised slightly to indicate that it applies
to chemicals used to treat water 1n cooling systems, not cooling towers.
The definition of the term "cooling tower" has not changed. These changes
make 1t clear that the prohibitions against distribution and use of
Cr+6-based water treatment chemicals apply only to open water
recirculation CCT's.
2.6.2 Comment
Two commenters (IV-D-13 and IV-D-26) urged EPA to complete the
analysis of ICT's promptly because they believe that the risk of exposure
to Cr+s emissions also exists with those towers.
Response. As discussed in the preamble to the proposed rule, the
differences between CCT's and ICT's are significant enough to warrant
separate regulatory analysis. Industrial process cooling towers are
different from CCT's in size, heat exchanger surface and bulk water
temperature, and heat exchanger construction materials. The higher
temperatures in industrial processes promote a higher corrosion rate in
ICT heat exchangers than is experienced in CCT condensers. Also, the
common heat exchanger construction material used in ICT systems, carbon
steel, 1s less resistant to corrosion than the copper used in most CCT
systems. The EPA is continuing to investigate ICT emissions and control
options in a separate study. A determination of the regulatory
requirements for ICT's will be made as expeditiously as possible.
2.6.3 Comment
One commenter (IV-0-24) indicated that CCT's should not be construed
to be similar or equivalent to ICT's such as those widely used throughout
major wet process industries.
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Response. As noted in the response to Comment 2.6.2, EPA is aware of
the differences between Id's and CCT's. These differences are discussed
'in the preamble to the proposed rule for Cr*"s-based water treatment
chemicals used in CCT's. A separate study 1s underway for ICT's.
2.7 MONITORING AND CONTROL
2.7.1 Comment
Two commenters (IV-0-12 and IV-D-24) indicated that Cr+6 is often
used as a tracer in nonchromate treatments because it is easier to
monitor, gives more accurate results than analyses for many nonchromates
(e.g., phosphonates), and is cost effective. Consequently, one commenter
(IV-D-24) requested that Cr+s at least be allowed as a tracer for use with
nonchromate water treatment programs. The other commenter (IV-D-12) would
like to find an easier test for phosphonate or another legal tracer.
Response. The EPA believes that there is not a justifiable need to
allow the use of Cr+6 as a tracer because acceptable alternatives exist,
such as molybdate and orthophosphate. Tracers are often included in water
treatment programs to aid in monitoring the level of corrosion inhibitor
in the water. Periodic analysis of the concentration of phosphonate or
other organic chemicals used in organic-based treatment programs is
necessary to ensure that adequate levels are maintained to inhibit
corrosion. Because these analyses are difficult and time-consuming, a
tracer such as molybdenum for which analysis is more simplified is
sometimes used. The ratio of the tracer to the corrosion inhibitor (e.g.,
phosphonate) is known, and fluctuations in concentration of the tracer
would indicate corresponding fluctuations in concentration of the
corrosion inhibitor.
Two water treatment chemical distributors have indicated that
molybdate can be used as a tracer in concentrations above about 2 ppm and
can be measured reliably by a simple colorimetric test.30'31 Another
distributor indicated that molybdenum concentrations as low as 1 ppm are
reliably measured by a colorimeter.32 One test kit manufacturer also has
developed a new method with which concentrations even less than 1 ppm can
be measured with a colorimeter. Several water treatment distributors
indicated that molybdenum concentrations lower than 1 ppm could be used as
a tracer, but more difficult and costly spectrophotometric analysis may be
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required.31'33'3** The distributor could perform these analyses at least
monthly, if necessary, because the CCT owners/operators would not likely
have the required equipment. According to one distributor, substituting
molybdenum at 2 ppm as a tracer would add about 20 percent to the cost of
the treatment program.32 Another distributor estimated that using
molybdenum at 1 ppm would increase the cost of the treatment program by 5
to 10 percent.31
Another tracer that can be used instead of Cr"1" or molybdate is
orthophosphate. Low levels (2 to 12 ppm) are added to the system, and
samples are analyzed colorimetrically for total phosphate. Any phosphate
that is contained in the raw water is accounted for in the analysis. A
low-level orthophosphate test kit costs about the same as chromate test
kits.35
The EPA agrees with the commenters that the phosphonate tests are
more difficult to perform and subject to more error than the tests for
tracers. However, conscientious operators can get acceptable results.
Furthermore, these results can be periodically confirmed by digesting a
sample and testing for phosphate. Sales representatives from some water
treatment distributors perform these tests on a monthly or quarterly
basis. Many of the major distributors are conducting research in this
area, and at least one test kit manufacturer recently developed a less
time-consuming digestion kit that it believes will be easier for the CCT
operators to use. In addition, a water treatment chemical distributor has
developed what it believes is a simpler and more reliable test for
phosphonate.7 These developments will make it easier for CCT operators to
use nonchromate treatment programs without tracers.
For the reasons discussed above, the final rule prohibits all uses of
Cr"*"6 at any concentration as a tracer in nonchromate water treatment
programs. The EPA believes that acceptable alternative tracers are
available and that accurate tests are available (and others are under
development) at a reasonable cost for tracers and for phosphonate.
2-70
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2.8 LEGAL CONSIDERATIONS
2.8.1 Comment
One commenter (IV-D-9) that advises clients on warning requirements
such as labels and material safety data sheets 1s concerned that
conflicting conclusions on the carc1nogen1c1ty of Cr+s and sodium
dlchromate among regulatory agencies could cause personal Injury liability
risks to Increase. The commenter Indicates that, 1n contrast to EPA's
position, the 1985 NIOSH Pocket Guide to Chemical Hazards states that Cr+6
from sodium dichromate is noncarcinogenic. Furthermore, in a
Toxlcological Profile, ATSDR concluded from the Steinhoff study that
sodium dichromate is only a weak carcinogen.
Response. The commenter's concerns regarding the conflicting
conclusions on the carcinogenicity of Cr"*"6 among regulatory agencies are
addressed in the response to Comment 2.2.2 in the Health Effects/Risk
section of this document. Based on evidence published since 1975, NIOSH
recommended to OSHA in 1988 that OSHA should consider all Cr*6 compounds
as occupational hazards. The EPA has commented on the ATSDR document,
which 1s stm 1n draft form, and recommended that ATSDR consider changing
its conclusions. The additional information provided in the response to
Comment 2.2.2 and in the response to Comment 2.2.1 regarding EPA's
conclusion on the carcinogenicity of Cr+s, should be helpful to the
commenter in developing appropriate advice for clients.
2.8.2 Comment
One commenter (IV-F-1 [Sefton]) believes that EPA's contention that
building owners would not risk liability by failing to add sufficient
biocide is not realistic. The commenter also believes it is likely that
sufficient biocides will not be added in many cases because operators that
can disregard biocides with chromate treatments may find it hard to break
old habits.
Response. The EPA did not contend that building owners would not
risk liability by failing to add sufficient biocide. In fact, EPA
believes that failure to add recommended amounts of biocides could result
in health problems and, possibly, in liability claims. Failure to add
biocides also can lead to excessive growth of algae and other micro-
organisms on the internal tower and heat exchanger surfaces. Such growth
2-71
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can result in decreased cooling efficiency and increased corrosion, both
of which cannot be tolerated in most CCT systems. Consequently, EPA
believes, contrary to the commenter's opinion, that building owners will
be conscientious in adding sufficient biocide in their water treatment
programs.
2.9 MISCELLANEOUS
2.9.1 Comment
One commenter (IV-D-13) believes that most middle-size to large-size
water treatment chemical distributors supply only small amounts of Cr*6-
based water treatment chemicals and that less than 5 percent of CCT's
under "professional" treatment currently use chromates. The commenter
believes that small water treatment chemical distributors and "do-it-
yourselfers" use chromate because of its low cost, convenience, and ease
of testing and control. Another commenter (IV-D-17) estimates that
25 percent of the CCT's in the commenter's area (Bartlett, Illinois) use
chromates.
Response. Based on discussions with several water treatment chemical
distributors, EPA believes that from 10 to 25 percent of the CCT's in the
U.S. are using Cr"l"6-based water treatment programs, although their use may
be significantly different in some regions of the country.1 The
commenter1s estimate appears to be lower than this range, but adding the
large number of small water treatment companies may bring the commenter's
estimate up to 10 percent.
2.9.2 Comment
One commenter (IV-F-1 [SeftonJ) believes that corrosion-related
failures of the tube sheets will increase, which will cause, among other
things, the release of several hundred pounds of ozone-depleting Freon
into the atmosphere per occurrence.
Response. Typically, tube sheets are constructed of carbon steel.
Therefore, the commenter's conclusion is predicated on the assumption that
nonchromate treatment programs cannot control corrosion in carbon steel.
However, as discussed in responses to Comments 2.1.6 and 2.1.7,
nonchromate treatment programs have achieved acceptable results even under
poor quality water conditions. To achieve acceptable results requires
proper monitoring, control, and maintenance of the treatment program and
2-72
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the CCT system. As an added precaution, the CCT operator could epoxy coat
the tube sheets. The CCT operators will rapidly identify and implement
successful programs and, considering the cost of neglect, they also will
Implement proper monitoring, control, and maintenance procedures.
Consequently, EPA does not believe tube sheet failures or Freon emissions
will increase.
2.10 REFERENCES FOR CHAPTER 2
Agency. Report 450/3-87-010a. March 1988.
2. Handbook of Industrial Water Conditioning. 8th Edition. Betz
Laboratories. Trevose, Pennsylvania. 1980.
3. Telecon. M. Cassldy, MRI, with D. Hasselbroek, Dowel!
Schlumberger. October 17 and 20, 1988.
4. Engelhardt, P., Johnson, K., and Metz, B JMolybdate Update -
Effective, Economical Programs. Cooling Tower Institute Paper
No. TP 87-10. New Orleans, Louisiana. February 1987.
5. Letter and Attachments. Sexton,-G., Betz Industrial, to
Stackhouse, D., EPA:SDB. September 26, 1988.
6. Telecon. D. Randall, MRI, with M. Hughes, Tlshman-Speyer
Properties. November 18, 1988.
7 Telecon. D. Randall, MRI, with H. Zamechek, Dexter Water Management
Systems. April 27 and September 9, 1988.
8. Steinhoff, 0., S.C. Gad, G. K. Hatfield and U. Mohr. Testing Sodium
Dichromate and Soluble Calcium Chromate for Carcinogenicity n
Rats. Bayer, A. G. Institute of Toxicology. 1983. Unpublished.
9 Lew L S and P. A. Martin. The Effects of a Range of Chromium
Material* on Rat Lung (draft). Sponsored by Dry Color Manufacturers
Association and others. 1983. Unpublished.
10 Hueper, W. C. Environmental Carcinogenesis and Cancers. Cancer
Res. 21:842-857. 1961.
11. Glaser, U., D. Hochrainer, H. Kloppel, and H. Oldiges.
Carcinogenicity of Sodium Dichromate and Chromium (VI/ IIOx de
Aerosols Inhaled by Male Wistar Rats. Toxicology. 42(2-3).219-32.
1986.
12 Levy, L. S., P. A. Martin, and P. L. Bidstrup. Investigation of the
Potential Carcinogenicity of a Range of Chromium Containing Materials
on Rat Lung. Br J Ind Med. 43(4):243-256. 1986.
2-73
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APPENDIX A.
CALCULATION OF NATIONWIDE COST EFFECTIVENESS
In Section 2.5, the cost effectiveness is calculated by a
conventional approach using a single discount, or interest, rate. Another
discount approach currently being considered by EPA is a two-stage
procedure that takes into consideration both the opportunity cost of the
displaced resources and the consumer rate of time preference. The
opportunity cost assumes the capital costs incurred by companies from
government action would displace other private investments. The consumer
rate of time preference assumes government action will increase operating
costs of companies that will be passed through to consumers in the form of
higher prices and, as a result, consumption of goods and services would be
reduced. Using the two-stage approach, the estimated capital costs are
annualized using the marginal rate of return on capital (interest rate).
Total costs over the life of the capital equipment then are discounted to
present value using a social rate of time preference (consumption rate of
interest). Benefits may be estimated with the same discounting
procedure. Calculations of the nationwide cost effectiveness based on the
conventional discounting approach and the two-stage discounting approach
are presented below. Additional information about the chemical costs,
capital costs, and annual incidence per CCT are presented in Section 2.5
and in docket items IV-B-1, IV-B-2, IV-B-3, and IV-B-4.
A-l
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A.I CONVENTIONAL APPROACH WITH 10 PERCENT INTEREST RATE
Annual chemical cost
difference between = $9,773,000
chromate and
nonchromate programs
A T A •* i $1,400 x 0.1 x l.l10 „ $100 x 0.1 x l.l3
Annual ized capital = — - - — - + - : - : -
cost per CCT 1.110-1 1.1 x (1.1-1)
+ S150 x 0.25 x 0.1 x l.l2
l.l2 x (1.12-1)
= $228 + $30 + $18
= $276/CCT
Annual ized nationwide
capital cost = $276/CCT x 37,580 CCT's
= $10,372,000
Total annual cost = $9,773,000 + $10,372,000
= $20,145,000
Annual benefit = 20 cases
Cost effectiveness = *00 = $l,000,000/case
A. 2 TWO-STAGE APPROACH WITH 7 PERCENT INTEREST RATE AND 3 PERCENT
DISCOUNT RATE FOR BOTH TOTAL COSTS AND BENEFITS
Annual chemical cost
difference between = $9,773,000
chromate and nonchromate
programs
10 3
,. . ... $1,400 x 0.07 x 1.07 _,_ $100 x 0.07 x 1.07
Annual ized capital = — - - — - + - : - :
cost per CCT 1.07-1 1.073 x (1.07-1)
+ $150 x 0.25 x 0.07 x 1.07*
1.072 x (1.072-1)
= $199 + $31 + $18
= $248/CCT
A-2
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Annualized nationwide
capital cost
Total annual cost
Discounted present value
of total annual cost
Discounted present value
of benefits
= S248/CCT x 37,580 CCT'S
= $9,320,000
= $9,773,000 + $9,320,000
= $19,093,000
_ $19,093,000 x (1.03lo-l)
0.03 x 1.0310
= $162,867,000
_ 20 cases x (l.Q310-l)
0.03 x 1.0310
* 171 cases
_ $162,867,000 = $952f000/case
171 cases
Cost effectiveness
A 3 TWO-STAGE APPROACH WITH 7 PERCENT INTEREST RATE. 3 PERCENT DISCOUNT
RATE FOR TOTAL COST, AND NO DISCOUNT FOR BENEFITS
The Office of Pesticides and Toxic Substances has suggested that a
separate analysis be evaluated using discounted cost and undiscounted
benefits.
Discounted present value of total annual cost = $162,867,000
Undiscounted present value of benefits = 20 cases/yr x 10 years
- 200 cases
Cost effectiveness
. $162,867.000 , $814§ooo/case
200 cases
A-3
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APPENDIX B.
APPROACH TO DATA GATHERING EFFORT
To respond to comments about water treatment program performance and
costs, EPA conducted a comprehensive data gathering effort. An attempt
was made to obtain information from several water treatment chemical
distributors, cooling tower users and equipment manufacturers for use in
responding to industry comments on the proposed rule. However, often
times little or no information was offered or supplied from the various
contacts made. Presented below is a summary of the contacts who provided
information used in responses to the public comments. The .information
obtained was sufficient to provide an adequate assessment and responses to
industry comments. Most of the major water treatment chemical
distributors, two small water treatment chemical distributors, an
automatic control equipment manufacturer, a company that cleans corroded
CCT systems, and a customer of the cleaning company provided some
information. All of the companies were contacted by telephone, and
followup letters were sent to some of the water treatment chemical
distributors.
The water treatment distributors were asked for (1) typical costs of
nonchromate and chromate programs, (2) case histories of nonchromate
treatment program performance and cost in poor quality water applications,
(3) types and costs of automatic control equipment needed for successful
operation of nonchromate treatment programs, and (4) prevalence of heavily
corroded systems on chromate programs and how these systems are cleaned
and/or switched to nonchromate treatment programs. Based on information
in the proposal BID, the distributors that were contacted represent over
75 percent of the water treatment industry.
B-l
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The automatic control equipment manufacturer was asked to provide
costs for typical types of equipment described by the water treatment
chemical distributors. Several of the water treatment chemical
distributors indicated that they used this manufacturers equipment. A
company that cleans corroded CCT systems was contacted for the cost of
cleaning, types of cleaning solutions, and the length of time required to
clean corroded systems. To confirm that heavily corroded systems can be
cleaned adequately, a customer of the cleaning company was also contacted.
8-2
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1. REPORT NO.
E?A-450/3-d7-OlOb
TECHNICAL REPORT DATA
(Please read fnstrucnons on the reverse before completing)
' M"'~~'——^™*^—1— IMI
4. TITLE AND SUBTITLE
Chromium Emissions From Comfort fooling Towers--
Background Information for Promulgated Standards
7. AUTHOR(S)
6. PERFORMING ORGANIZATION CODE
8. PERFORMING ORGANIZATION REPORT NO.
"PERFORMING ORGANIZATION NAME AND ADDRESS
Office of Air Quality Planning and Standards
U. S. Environmental Protection Agency
Research Triangle Park, N.C. 27711
12 SPONSORING AGENCY NAME AND ADDRESS
Director of Air Quality Planning and Standards
Office of Air and Radiation
U. S. Environmental Protection Agency
Research Triangle Park, N.C. 27711
15. SUPPLEMENTARY NOTES
. RECIPIENT'S ACCESSION NO.
i. REPORT DATE
January 1989
10. PROGRAM ELEMENT NO.
Ti. CONTRACT/GRANT NO.
S8-02-3317
13. TYPE OP REPORT AND PERIOD COVERED
Final
14. SPONSORING AGENCY CODE
EPA/200/04
| O. ^D*#l l«*-»wi
A final rule for the control of hexavalent chromium emissions from comfort cooling
Jowlrf is tain? promulgated under authority of Section 6 of the Toxic Substances
Control Act The final rule prohibits both the use of Cr* 1n CCT's and the
distribution in commerce of Cr+* for use in CCT's. The rule would apply to existmg
and new CCT's ThS document contains a summary of changes to the rule made since
proposal, a summary of the impacts of the promulgated rule, and a summary of the
public comments on the proposed rule and EPA's responses.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
COS>
Air pollution
Pollution control
Comfort cooling towers
Hexavalent chromium
',,'ater treatment chemicals
Air pollution contro
18. DISTRIBUTION STATEMENT
Unl irnited
19. SECURITY CLASS (
Unclassified
87
20. SECURITY CLASS (Thispage)
Unclassified
22. PRICE
EPA Form 2220-1 (Rev. 4-77) PREVIOUS EDITION is OBSOLETE
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